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In the present investigation, the sol–gel technique was utilized to synthesize pure and Fe3+ doped cerium oxide (CeO2) nanoparticles. The synthesized nanomaterials underwent extensive analytical and spectroscopic characterization process to ascertain their physicochemical properties. The analysis of powder X-ray diffraction (PXRD) patterns revealed that the incorporation of 0.5 M Fe resulted in a decrease of crystallite dimensions to 11 nm, in contrast to the 44 nm observed in the undoped CeO2. Moreover, the introduction of Fe impurities was found to narrow the energy bandgap, evidenced by a decrease from 3.00 eV in pure CeO2 to 2.20 eV in CeO2 doped with 1.5 M Fe, thereby enhancing the material’s optical absorption into the visible light range. An examination of electron density distribution provided insights into the bonding characteristics of the materials post-synthesis. The photocatalytic efficiency of the Fe-doped CeO2 nanoparticles was evaluated through degradation of methyl orange (MO), under the influence of visible light irradiation. Remarkably, the Fe-doped CeO2 nanoparticles exhibited a significant photocatalytic activity, culminating degradation efficiency of 88% of MO within a span of 60 min. This pronounced photocatalytic efficiency underscores the potential application of Fe-doped CeO2 nanoparticles in the domain of environmental cleanup. [ABSTRACT FROM AUTHOR]

In this work, we have fabricated a novel electrochemical biosensor based on TiO2/PS. Heterostructure by sol–gel assisted with spin-casting technique. XRD profile showed the tetragonal phase of TiO2 thin films. SEM images observed the nanoporous-like surface morphology. The film has 78 nm of grain size calculated from AFM analysis. The PL spectrum recorded a strong emission peak at 485 nm, 530 nm, and 545 nm due to blue and green emission. The enhancement of the electrochemical reaction was analysed by cyclic voltammetry (CV). The fabricated electrode has shown the sensitive and stable detection of carbohydrates. The more consistent results showed that TiO2/PS electrode is a promising material for the carbohydrates biosensor. Most importantly, the TiO2/PS electrode achieved a correlation between the coefficient (R2) and sensitivity 0.99 and 26 μA mM−1 cm−2 of glucose. Similarly, 0.98 & 16 μA mM−1 cm−2 for sucrose and 0.96 & 11 μA mM−1 cm−2 for starch. [ABSTRACT FROM AUTHOR]

This work developed a hydrothermal process for the effective synthesis of Sn-doped graphene nanoparticles. To prepare the samples at 180°C in carbon tetrachloride organic solvent and different levels of Sn concentrations (0.3, 0.6 and 0.9) were used. A variety of analyses were carried out on the prepared materials, including XRD, SEM with EDX, TEM, AFM, UV, PL and I-V. The XRD analysis revealed good crystallinity and hexagonal structure in Sn-doped graphene nanoparticles. An SEM micrograph reveals that the morphology is flower, nano-chalk pieces and agglomerated at some places. The TEM images clearly specify the spherical and are agglomerated at some places. Topography images (AFM) show that hydrothermal treatment at different concentrations influences the growth of Sn-doped graphene NPs. The bandgap of Sn-doped graphene nanoparticles is estimated as 2.23, 3.7 and 4.7 eV. All the p-Si/n-graphene diodes exhibited excellent rectification with less reverse current. The impact of metal (Sn) doping concentration favourably decreases the n value of the p-Si/n-Sn-doped graphene diode. In the current work, it is shown that the p-Si/n graphene diode is highly sensitive to various concentrations of graphene. [ABSTRACT FROM AUTHOR]

NiCo2S4 is a promising material for use in supercapacitors due to its high conductivity and redox activity. However, its cycling stability is poor due to the structural degradation of the electrode caused by the redox reaction. NiCo2S4 is encased with an ultrathin graphene oxide layer to produce a core/shell structure (NiCo2S4@GO). We present a simple approach for the fabrication of NiCo2S4/graphene composites. With a specific capacitance of 1100 F g−1 and a current density of 1 A g−1, the NiCo2S4@GO composite demonstrates exceptional electrochemical performance. A hybrid supercapacitor assembled using the synthesized NiCo2S4@GO as a positive electrode and porous carbon as a negative electrode demonstrates a high energy density of 26.9 W h kg−1 at a power density of 658 W kg−1 in the voltage range 0–3.5 V. After 10,000 charge/discharge cycles, the device still retains 78% of its initial capacitance. [ABSTRACT FROM AUTHOR]

In this study, the Schottky diodes based on an interfacial layer of Sr–W thin film were fabricated. Thin films were coated on glass and silicon substrates by low-cost jet nebulizer spray pyrolysis (JNSP) coating technique with optimized substrate temperatures 500 °C. Structural, surface morphology, optical, and electrical characteristics of Sr–W thin film were investigated. In particular, the I–V characteristics of Cu/Sr–W/n-Si diodes in dark and light excitations were analysed. The maximum barrier height (Φb) for the diode fabricated 6 wt% tungsten under xenon lamp light irradiation was observed at 0.83 eV. Also, near ideal ideality factor (n) of the diode parameters, it was found at highest 6 wt% tungsten. The results show that diodes are more appropriate for the improvement of good quality photodiodes as well as photodetector applications. [ABSTRACT FROM AUTHOR]

The jet nebulizer spray (JNS) pyrolysis method has been successfully employed to grow CuO thin films at various substrate temperatures, ranging from 300 to 600˚C. The XRD analyses revealed the monoclinic phased polycrystalline growth of the samples and exhibited the strong influence of substrate temperature (ST) on the crystallite sizes. Optical transmission and bandgap studies also showed that sample bandgaps clearly rely upon the growth temperatures. The SEM micrographs displayed the agglomerated growth of particles having golf ball-like structures. The occurrence of Cu and O in the samples were confirmed through EDS analyses. The studies on DC electrical conductivities (I-V curves) also show strong dependency on the ST. A p-CuO/n-Si diode was fabricated at the ST of 600˚C and the diode parameters like barrier height ( φ b ) and ideality factor (n) were determined under light and dark conditions. [ABSTRACT FROM AUTHOR]

The present research explores the fabrication of a metal insulator semiconductor Schottky barrier diode (SBD) with rare earth metal oxide (Yb2O3) thin films as insulators that are effectively developed on a large scale using the low-cost jet nebulizer spray pyrolysis technique (JNSP). The Yb2O3 thin films are deposited at various substrate temperatures (350 °C–550 °C) to ascertain its influence on the characteristic properties of the material. The structural, morphological and opto-electrical properties are investigated using various characterization techniques. Here, X-ray diffraction (XRD) analysis revealed the single crystalline cubic crystal structure of Yb2O3 thin films. Field emission scanning electron microscope (FESEM) images show the presence of uniformly distributed cage and globular like structures spread over the entire surface of the Yb2O3 films. The elemental composition study demonstrates the presence of Yb and O. The optical direct energy band gap of Yb2O3 thin films have been analyzed through UV-Visible spectra. Current – voltage measurements were analyzed in dark and light conditions for the Al/Yb2O3/p-Si structured Schottky barrier diodes (SBDs) which are fabricated with interfacial layers at different substrate temperatures. Further, the functionality of the SBDs was tested at different temperatures ranging from 30 °C to 150 °C. The experimental results of all SBDs indicate a linear reduction in the ideality factor (n) up to 2.537 and 2.059 with a slight increase in the effective barrier height (ФB) of 0.789 eV& 0.638 in dark and light conditions, respectively. The SBD fabricated at 550 °C recorded good performance, which will be suitable for thermal dependent electronic device applications. [ABSTRACT FROM AUTHOR]

Herein, we have studied the influence of terbium (Tb) doping in bismuth ferrite (BiFeO3/BFO) nanoparticles towards its photocatalytic activity by varying the concentration of Tb such as Bi1−xTbxFeO3, x = 0, 1, 3, 5% through a simple hydrothermal method. The obtained samples are characterized using XRD, TEM, XPS, and UV–Vis diffuse reflectance spectroscopy and studied their photocatalytic properties by degrading the rhodamine B (RhB) dye molecules under sunlight illumination. The XRD results confirmed a gradual transformation of crystal structure of BFO from rhombohedral to orthorhombic structure with the increasing concentration of Tb. Dopant induced size reduction in particles is confirmed through TEM and the obtained results revealed the average particles size of 5% Tb dopant BFO around 40 to 80 nm for 5% Tb doped BFO. It indicates that the Tb doping in BFO could considerably affect the photocatalytic activity, and accordingly, the photocatalytic performance is gradually enhanced with increasing Tb content up to an optimum level. To understand the improved mechanism of photocatalytic degradation by Tb-doped BFO, the free radicals trapping tests and photoluminescence are carried out. Based on these outcomes, the improved catalytic activity of Tb-doped BFO is attributed to its reduced bandgap energy from 2.35 to 2.29 eV, improved optical absorption profile, the effective charge separation and transfer of photo-induced charge carriers with increased recombination resistance in the system and accordingly, a possible photocatalytic mechanism of Tb-doped BFO is also proposed. [ABSTRACT FROM AUTHOR]

We report on the fabrication of p-Si/n-CdO and p-Si/n-CdIn2O4 junction diodes using chemically prepared pure CdO and In 5–20 wt.%-doped CdO nanoparticles. The cadmium oxide (CdO) and indium-doped cadmium oxide (ICO) nanoparticles were characterized using x-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, energy dispersive analysis, high-resolution transmission electron microscopy (HRTEM), UV-Vis analysis, photoluminescence (PL) and electrical conductivity measurements. The strongest orientation along the (111) plane for CdO indicates a fcc crystal system. The average particle size of ICO nanoparticles vary from 26 nm to 41 nm. The FTIR bands for ICO samples at 508–511 cm−1 was strongly remodeled while increasing the doping concentration of In at 15 wt.%. HRTEM revealed a clear spherical morphology ~16.28 nm of average particle size for the ICO with 20 wt.% In. Moreover, a maximum electrical conductivity of 15.084 × 10−10 S cm−1 with higher transmittance range of about 76.11% was achieved. The photosensitivity of the p-Si/n-CdIn2O4 diode varied from 103 to 104 %. Also, high quantum efficiency ~225.92% and specific detectivity 5.1952×1011 Jones were found for p-Si/n-CdIn2O4 photodiode. These outcomes suggest that the developed p-Si/n-CdIn2O4 diode is suitable one in the fabrication of UV photodetector and solar cell devices for electronic communication. [ABSTRACT FROM AUTHOR]

An ultrahigh photosensitive diode was developed using a Cu-doped CeO2 thin film through spray pyrolysis processing, which has made a unique contribution in the field of optoelectronic device fabrication process. Phase identification revealed a good arrangement of atoms in the as-prepared nanostructured thin films via structural analysis. The formation of wire-shaped nanorods was confirmed. Elemental distribution and their valence states were systematically monitored using X-ray photoelectron spectroscopy analysis, where the presence of Ce3+ was evidenced. Good mechanical properties were obtained owing to the Cu-doping in the cerium host matrix, which was investigated by nano-indentation. Bandgap energy fluctuation was the root cause for electrical conductivity. The present work revealed a decrease in the band gap energy upon Cu-doping alters the electrical conductivity. An as-fabricated photodiode demonstrated superior detectability upon Cu-doping. In the depletion region, on account of a high surface-to-volume ratio, the generation of electron–hole pairs increased along with photoresponsivity with increases in the quantum efficiency and current gain. [ABSTRACT FROM AUTHOR]

In this work, we have successfully prepared the nano-coral to be intact with the mesoporous of Sn-HfO2 thin films through the (jet nebulizer spray pyrolysis) JNSP technique from different Sn (5, 10, 15 Wt.%) to improve the MIS Schottky diode Al/Sn-HfO2/n-Si. To achieve the phase transformations (monoclinic to orthorhombic) in pure hafnium oxide thin films, we have added the Sn ions as the composite at optimized temperature 600 °C. The XRD characteristic used to determine the structural parameters such as the phase, grain size for pure HfO2, and composite Sn-HfO2 films. The mesoporous with irregularly shaped balls and nano coral-like morphology have been observed through FESEM images. The absorption coefficients and bandgap energy have been determined from the UV Vis spectrum. The EDAX elementary analysis has confirmed the presence of Sn, Hf, O elements in each film. The XPS spectrum has confirmed Sn's presence and binding peak with a spin-orbit on the films' surface. I-V curves of forward and reverse bias determine the barrier height, ideality factor, and saturation currents from the thermionic emission theory. All the Al/Sn@HfO2/n-Si diode parameters are strongly improved after the incorporation of Sn ions. [ABSTRACT FROM AUTHOR]

In this work, pure and Mn-doped nickel ferrite (Ni1-xMnxFe2O4, x = 0, 3, 6, 9, and 12 wt%) thin films were prepared using facile nebulizer spray pyrolysis technique. The effect of Mn concentration on the structural, optical, and magnetic properties was studied. The XRD pattern confirms the cubic spinel structure of Ni1-xMnxFe2O4 thin films and reveals the preferred orientation along the (311) direction for each film. Moreover, the average crystallite size (D) is found to increase from 13 to 30 nm with increasing Mn concentration. The FESEM micrographs exhibit randomly arranged plate-like and rice-like grains. The elements such as Mn, Ni, Fe, and O are confirmed by the EDX analysis. The optical band gap energy (Eg) varies between 2.90 and 3.60 eV. The Ni1-xMnxFe2O4 film prepared with 3 wt% of Mn exhibits superior ferrimagnetic behavior with the highest value of ηB (57.31) due to the high crystallinity, packing density, and smooth surface of the film. The present work shows that the facile nebulizer spray pyrolysis technique can produce high-quality Ni1-xMnxFe2O4 thin films with good magnetic properties. [ABSTRACT FROM AUTHOR]

Herein, indium doped tin oxide (ITO) nanoparticles were produced via co-precipitation process and used to develop a photodiode (p-Si/n-ITO) via a cost-effective spin coating process. X-ray diffraction (XRD) study revealed a mixed crystalline phase of tetragonal and cubical structures for the doped samples indicating nanocomposite formation. The effect of indium ion vibrations of OH bonds is observed by Fourier transform infrared (FTIR) spectra. The fine nanoparticles (NPs) synthesis was confirmed by SEM and NPs are of spherical shape confirmed via TEM. The maximum absorbance 262 nm and minimum optical band gap Eg = 2.8 eV was attained for 5 wt.% of In. From electrical studies, the conductivity was found to be in the range 1.4767 × 10−6 and 0.74 × 10−13 S/cm. The p-Si/n-ITO diode was fabricated with 5 wt.% of In and its ideality factor (n), barrier height (Φb), photosensitivity (PS), responsivity (R) and specific detectivity (D*) were examined in dark and light surroundings. The diode exhibited good Ps = 21% and D* = 3.38 × 107 Jones. The output results indicate that the developed device will be good in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Zn-doped TiO2 films were deposited on ultrasonically treated alumina substrates via the automatic nebulizer spray pyrolysis method. In this study, the thickness of the as-prepared films was gradually reduced, and their Brunauer–Emmett–Teller (BET) surface area and pore volume results were notably improved; in addition, values for the blue-shifted sharp edge absorption with an enlarged bandgap (Eg) were revealed in the deposited films. The agglomerated granular form has evolved into tiny grains with porous brighter particles scattered over the surface of the coated films. The sensing performance to reducing gases for combustible gas of ammonia (NH3) and volatile organic compounds of methanol (CH4O) and formaldehyde (HCHO) with the function of operating temperature and gas concentration were studied, and the highest sensing response of the hazardous formaldehyde (HCHO) reducing gas was noticed. [ABSTRACT FROM AUTHOR]

In this work, we present the synthesis and characterization of molybdenum oxide (MoO3) nanoparticles (NPs). The MoO3 NPs were coated on silicon (Si) wafer to fabricate n-MoO3/p-Si diode by the spin coating method. X-ray diffraction (XRD) profiles clearly show the crystalline nature of all specimens with an orthorhombic crystal system. Stretching and bending vibrations of molybdenum-oxygen were confirmed by the Fourier transform infrared analysis. The maximum absorbance was observed for MoO3 NPs prepared from Nitric acid (HNO3). Nano flakes like morphology were seen by scanning electron microscopy (SEM), and elemental dispersion spectral analysis approved expected Mo and O elements in the final product. Transmission electron microscopy (TEM) analysis of the as-prepared samples indicates a single-phase orthorhombic crystal structure. Electrical conductivity results show that synthesized samples are having semiconducting behavior. It is noted that the p–n junction diode prepared with Hydrochloric acid (HCl) has better rectifying behavior with lower ideal factor (n) values of 2.47 than the other sample. [ABSTRACT FROM AUTHOR]

Pure CeO2 and Ni-doped cerium oxide (NDC) films were deposited by a facile and economic jet nebulizer spray pyrolysis (JNSP) process at 450 ºC substrate temperature. Here, efforts have been done to enhance the performance of the NDC diode using various doping concentrations of Ni (0, 2, 4, and 6 wt%). X-ray diffraction revealed polycrystalline film formation with a cubic crystal structure and the crystallite size of CeO2 was increased from 10 to 21 nm on Ni doping. EDX study confirms the presence of Ni in NDC films. FESEM explicitly shows fine spherical grains-like morphology. The optical studies indicate the reduction in the bandgap of CeO2 from 3.30 to 2.86 eV on Ni doping. The Photoluminescence (PL) spectrum proves that the oxygen vacancy is created in the CeO2 thin films while doping with Ni which leads to the blue shift and intensity enhancement of emission peak. NDC film prepared with 6 wt% showed a higher electrical conductivity ~ 3.76 × 10–10 S/cm which indicates that it is suitable for photodiode fabrication. The fabricated p-Si/n-NDC photodiode works with superior parameters like ideality factor (n) and barrier height (ΦB) under dark and illuminated conditions. The saturation current (Io) of the p-Si/n-NDC diode is varied from ~ 2.69 × 10–05 to 6.57 × 10–04 A with Ni concentrations. The estimated n and ΦB values of the p-Si/n-NDC junction diode are found to be decreased from 7.6 to 2.5 and 0.72 to 0.60 eV. These outcomes indicate that the fabricated photodiode is a useful element in optoelectronic devices. [ABSTRACT FROM AUTHOR]

In the proposed work, the thin films have been effectively synthesized by doping the post-transition metal with rare earth metal (In-Yb2O3) on a large scale using a low-cost jet nebulizer spray pyrolysis technique at different indium (In) doping concentration (0, 1.5, 2.5, 3.5, and 4.5 wt %) with optimized substrate temperature 550 °C. The structural, morphological and opto-electrical properties are investigated using various characterization techniques. Here, the high-quality single-phase cubic structure film was observed by X-ray diffraction (XRD) analysis. The field emission scanning electron microscope (FESEM) image reveals the change in morphology with indium (In) concentration in Yb2O3 thin films. The elemental composition study approves the presence of Yb, In and O. The transmittance, optical indirect energy gap of In-Yb2O3 films have been analyzed by UV–Vis spectra. DC electrical analysis records an improved conductivity and reduced average activation energy for higher doping content of In-Yb2O3 thin films. Notably, all the diodes shows positive photo conducting properties. Specifically, when the Al/In-Yb2O3/p-Si Schottky barrier diode fabricated with higher doping concentration such as 4.5 wt. % produces the minimum ideality factor (1.791), maximum barrier height (0.692 eV) and higher photosensitive diodes. [ABSTRACT FROM AUTHOR]

Silver–palladium (Ag/Pd) bimetallic nanoparticles were synthesized by greener way using Catharanthus leaf extract. The synthesized silver/palladium bimetallic nanoparticles were used to degrade the safranin O textile dye through photo catalytic activity and the free radical scavenging property was evaluated by DPPH assay test. Silver/Palladium bimetallic nanoparticles were synthesized by biogenic reduction method using silver nitrate and palladium chloride precursors assisted with CRL extract. The synthesized Ag/Pd bimetallic nanoparticles' morphological and particle size were evaluated by the SEM/TEM image. The particle size was found to be within the nanoscale range of 15–30 nm. The 98% maximum dye degradation for 40 min time duration was achieved by the photocatalytic activity of silver/palladium bimetallic nanoparticles through UV light irradiation on safranin O textile dye and simultaneously antioxidant activity of silver/palladium bimetallic nanoparticles was also tested through DPPH assay test. The free radical scavenging efficiency was calculated for extract and extract with silver/palladium nanoparticles and was found to be 48.2% and 70.2%, respectively and revealed that the silver/palladium nanoparticles have 2.34 times higher scavenging activity when compared with Catharanthus leaf extract. [ABSTRACT FROM AUTHOR]

The physical, chemical, and electrical properties of materials are influenced by the shape, size, and surface morphology such as rod, core-shell, network, and flowers. Herein, hollow nano-belt SnS/NiS composite structure was synthesized by the high-temperature wet chemical method in the presence of as-synthesized SnS as seed, and its photoresponse was evaluated by fabricating P-N junction photodiode using n-type Si substrate. Phases that are presented in the synthesized samples were characterized by powder diffraction method. Morphology of SnS and hollow nano-belt formation in SnS/NiS was confirmed by transmission electron microscopy. The solution-processed photodiode was fabricated using synthesized p-type SnS and SnS/NiS on n-Si substrate, and photoresponse was compared with each other. Observed photodiode results revealed that hollow nano-belt based p-SnS/NiS/n-Si photodiode has better photoresponsivity 98.95 mA/W than photodiode fabricated using bare SnS sample. Also, its photosensitivity (275.989% at 3 V), EQE (38.371%), and D* (2.0080 × 1010 Jones) are noticed to be higher when compared with p-SnS/n-Si diode. The enhanced values of fabricated diode make it suitable for high photodetection applications. [ABSTRACT FROM AUTHOR]

Nebulizer spray pyrolysis (NSP) technique has been successfully employed for the deposition of well-dispersed highly homogeneous spindle-shaped yttrium-doped cerium oxide (YDC) films. Optical studies revealed a decreasing trend of transmittance with the increasing Y doping percentage up to 20% and then increase in transmittance at 25% either due to the increased crystal defect induced photon scattering or the increased metal-to-oxygen ratio at higher Y doping. PL spectra showed four distinct broad peaks at 3.34 eV (near-band-edge emission (NBE) at UV), and 3.14, 2.91 and 2.65 eV (deep-level emission (DLE) in the visible spectra at violet, blue and green, respectively) corresponding to the wavelengths 365, 394, 425 and 465 nm, respectively. XRD studies confirmed the polycrystalline cubic fluorite single-phase structures preferentially orientated along (200) and (111) reflections without any impurity peaks. SEM images showed that YDC films are grown with small granules containing spherical-shaped particles having many cracks and patches. The average width of tiny granules inside the well-aligned taper-like structures is found within the order of 138 nm. The observed changes in the rectification ratio of p-Si/n-YDC diode with voltage are allied to the corresponding changes in both series (Rs) and shunt resistances (Rsh) of the heterojunction. The transient photocurrent characteristics indicate that the prepared heterostructure is highly stable and has quick response, which advocates the use of prepared heterojunction device in UV detector and white light photodetector applications. [ABSTRACT FROM AUTHOR]

The presence of carcinogenic dyes in industrial wastewater is a serious problem that hazards the water bodies and nano-catalysts are key members that are used to purify it. Therefore, this work investigates the synthesis of tungsten oxide (WO3) nanoparticles with various annealing temperatures in the range of 100–600 °C by the co-precipitation method for photocatalysis applications. The improvement in crystallinity of the nanoparticles achieved through annealing temperature and the crystallite size was an increase from 10 to 34 nm. The structural parameters of the prepared samples were characterized using XRD reveals the formation of stable monoclinic structure. FESEM morphological images confirmed the formation of irregularly shaped nanoplates. HRTEM and SAED patterns confirmed the growth of nanocrystalline WO3 nanoparticles. Parameters like (hkl) planes and interplanar spacing values obtained from HRTEM studies agreed well with the results of XRD. The elemental presence and chemical compositions were confirmed from EDS and XPS studies, respectively. The presence of functional groups has been verified through FTIR spectroscopy studies. Considerable decrements in the energy gap of WO3 NPs were observed with annealing from 2.89 to 2.61 eV. The defects/oxygen deficiencies were examined through photoluminescence. The photocatalytic performance of WO3 NPs was assessed by degrading the methylene blue dye. The parameters obtained from Pseudo first-order kinetic studies confirmed that 600 °C annealed WO3 NPs have higher photocatalytic activity. [ABSTRACT FROM AUTHOR]

The advancement of p–n photodiode fabrication employing rare-earth materials has created cogent interest in the field of semiconductor device technology. We report on the formation of pure and Sn-doped CeO2 thin films assembled through spray pyrolysis technique to enhance the p-Si/n-Sn:CeO2 diode performance. A polycrystalline nature of cubical crystal structured Sn-CeO2 thin films was developed on glass slides with various doping levels of tin (0, 2, 4 and 6 wt%). The crystallite size was found to decline with increasing Sn wt%. A uniform surface with tiny spherical-like crystallite grains was observed through the FE-SEM microscope. The existence of Sn ions with the CeO2 system was confirmed by the EDX and XPS spectrum. The effect of Sn doping on the optical absorption and band gap of CeO2 was evaluated, in which the 2 wt% Sn exhibited lower Eg value with maximum absorption. The Sn ions enhanced the electrical conductivity suggesting the semiconducting nature of the films. The p-Si/n-Sn:CeO2 diode was fabricated, and its performance was analyzed under dark and light intensity of 100 mW/cm2. The photosensitivity of the device varied from 17.11 to 671.65%. The ON–OFF photoresponse of 6 wt% Sn is relatively higher than that of pure CeO2. [ABSTRACT FROM AUTHOR]

The WO3 thin films and p-Si/n-Ni@WO3 junction diodes are prepared with different wt% of Ni. The XRD profiles confirm that the monoclinic crystal system with a preferential orientation of (0 2 0) plane, in which their crystallite size is reduced from 28 to 14 nm with the rise of Ni content in WO3. From SEM images, the randomly arranged plate-like grain structure was observed for grown films and grain size reduces with an increase in Ni dopant concentration. The expected elements of Ni, W, and O are confirmed by the EDX spectrum and their ratio of composition was obtained. The UV–Vis-NIR spectra reveal that the 4 wt% of Ni@WO3 film exhibits a higher transmittance (~ 80%) with a low bandgap (Eg = 2.84 eV) value. The d.c. electrical conductivity increased with an increase in temperature for each Ni-doped WO3 films. The device ideality factor (n) and barrier height (ΦB) values were found to be decreased with a rise in Ni doping concentration. The better performance of the fabricated diode is observed p-Si/n-4 wt% of Ni@WO3 heterojunction diode with n = 1.820 and ΦB = 0.759 eV values. The obtained results suggest that the p-Si/n-Ni@WO3 diode is more suitable for optoelectronic device applications. [ABSTRACT FROM AUTHOR]

In this work, we report a p-Si/n-CeO2 junction diode fabricated by a cost-effective and large-area deposition technique of jet nebulizer spray pyrolysis. The n-CeO2 layer was coated on four different substrate temperatures (Tsub) 350, 400, 450, 500 °C and their properties were studied by various techniques like XRD, FE-SEM with EDX, UV–Vis and I–V characterization. XRD pattern confirmed a cubic fluorite crystalline phase of CeO2 thin films with preferential growth along (2 0 0) direction. A smooth surface with inter-connected smaller grains was recorded by FE-SEM micrographs and also the existing elements Ce and O have been confirmed. For Tsub of 450 °C, an exceptional optical absorption with smaller band energy of 3.3 eV was recorded in the UV–Vis spectrum. The electrical conductivity results indicated that all the films are semiconducting in nature. I–V characteristics of all the fabricated diode showed better rectification in dark with excellent photovoltaic characteristics under light exposed condition. The photosensitvity of the diode varied from 21.94 to 1093.75% with substrate temperature. Our results strongly suggested that rare-earth based p-Si/n-CeO2 diodes are suitable for future applications in ultraviolet photo-detector and photo-diode. [ABSTRACT FROM AUTHOR]

Octahedral indium oxide thin films with different precursor concentrations of 0.05, 0.075, 0.1 and 0.125 M were coated on glass substrates at 450 °C using jet nebulizer spray pyrolysis technique. Surface morphology of the prepared samples showed closely packed octahedrons for all concentrations. The measured root-mean-square value of the films was varied between 40.45 and 188.98 nm with increased precursor concentrations. From optical analysis, the calculated optical band gap was continuously decreased with increase in precursor concentrations. A slight blue shift was recorded through the PL spectrum while increasing the precursor concentration due to the oxygen vacancies. The nature of electrical conductivity of the In2O3 films was analysed. Interestingly, we have calculated two types of activation energies in the In2O3 films one is corresponding to low temperature and another is higher temperature. Further, p-Si/n-In2O3 junction diodes are fabricated with different precursor concentrations. Particularly, the 0.075 M of p-Si/n-In2O3 junction diode recorded a minimum ideality factor of n = 2.64 under light exposed condition, confirming the photo-conducting nature of the diodes in visible wavelength range. [ABSTRACT FROM AUTHOR]

Highly oriented ultrathin MoO3 nanoplate thin films have been synthesized on a large scale using a low-cost spray pyrolysis technique at different substrate temperatures (350°C, 400°C, 450°C, and 500°C). High-quality single-phase orthorhombic α-MoO3 nanoplate film was observed by x-ray diffraction analysis. The surface morphology of the coated films was analyzed by field-emission scanning electron microscopy, revealing two different surface structures, viz. nanorods and nanoplates. Under atomic force microscopy, the surface roughness of the films was found to decrease with increasing substrate temperature. The optical properties of the α-MoO3 nanoplate thin films were analyzed by ultraviolet–visible and photoluminescence spectroscopy. The optical bandgap varied from 2.8 eV to 3.2 eV, recording a red-shift in the emission, with increasing substrate temperature from 350°C to 500°C. The electrical conductivity was also found to increase linearly with increasing substrate temperature. Various photodiode parameters such as ideality factor (n), barrier hight (ФB), photo sensitivity (PS), resistivity (R), quantum efficiency (QE) and detectivity (D*) were calculated for different light intensities from 0 mW/cm2 to 120 mW/cm2 based on the I–V characteristic. The diode fabricated at 500°C showed a remarkably high photosensitivity and specific detectivity of 610.51% and 1.149 × 1011 Jones when measured at 120 mW/cm2. [ABSTRACT FROM AUTHOR]

Monoclinic WO3-nanoplate arrays have been effectively deposited via simple jet nebulizer spray pyrolysis technique at an optimized substrate temperature of 400 °C. These WO3-nanoplate arrays were used as an insulating layer in the metal–insulator–semiconductor (MIS) structure based Schottky barrier diodes. The effect of WO3 mol concentration during the deposition process was systematically interpreted with respect to the structural, morphological, optical and electrical properties of WO3-nanoplate array films. XRD pattern exposed the polycrystalline nature of the prepared films with a monoclinic phase. At higher concentration of 0.25 M WO3-nanoplates were firmly interconnected together and has been analyzed by a FE-SEM. From UV–Vis spectroscopy, the band gap values of the WO3 were found to vary from 3.2 to 3.4 eV with mole concentrations. DC electrical study recorded a steep increase in the electrical conductivity for the film prepared with 0.2 M of WO3. Notably, all the diodes exhibited positive photoresponse under illumination. Particularly, the MIS diode fabricated with 0.2 M revealed higher photoresponsivity and sensitivity of 960.85% and 33.40 mA W−1 respectively. [ABSTRACT FROM AUTHOR]

The influence of nickel (Ni) doping concentrations on structural, optical, electrical and diode properties of molybdenum trioxide (MoO3) thin films has been studied systematically. Ni-doped MoO3 films and diodes were prepared for various doping concentrations of Ni such as 0, 3, 6 and 9 wt.% by jet nebulizer spray (JNS) pyrolysis technique. The structural properties of Ni-doped MoO3 films were analyzed by X-ray diffraction (XRD) pattern and scanning electron microscopy (SEM). The prepared films were exhibited in the orthorhombic crystal structure and sub-microsized plate-like surface morphology. The energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the presence of Ni, Mo and O elements in the prepared films. Ultraviolet–visible (UV–vis) analysis results showed that the absorbance decreases with the increasing of Ni doping concentration and the minimum band gap energy (Eg = 2.25) was obtained for 9 wt.% Ni-doped MoO3 film. From current–voltage (I–V) characterization, the conductivity is increased by increasing the Ni doping concentration in MoO3 thin films. The diode measurements were performed in darkness and under light illumination of a halogen lamp. The methods of I–V, Cheung's and Norde were used to calculate the diode parameters of ideality factor (n), barrier height (Φb) and sheet resistance (Rs). Also, the light ON/OFF switching response of the fabricated n-NiMoO3/p-Si diodes was analyzed. [ABSTRACT FROM AUTHOR]

Metal-doped tungsten trioxide (M = Cd, In, and Sn:WO3) thin films were prepared using sol–gel spin-coating and their structural, optical, electrical properties were studied for the fabrication of p–n heterojunction diode. X-ray diffraction (XRD) analysis revealed that Cd, In, and Sn dopants have a strong influence on the lattice parameters and defect factor without making any changes in the structure. Scanning electron microscope (SEM) images reflect that the dopants have a strong impact on the surface morphologies of the WO3 thin film. The UV–visible analysis shows a high optical transmittance (∼82%) and variation in the bandgap was also obtained. The dc electrical conductivity (σdc) indicates that the band conduction mechanism is predominant in the pure and doped M:WO3 thin films. Current density–voltage (J–V) characteristics of WO3/p-Si, Cd:WO3/p-Si, In:WO3/p-Si, and Sn:WO3/p-Si diodes were measured under dark and illumination conditions. In which, the Sn:WO3/p-Si diode exhibits better performance with good ideality factor (n = 2.6) and barrier height (ФB = 0.90) values for under illumination. Most importantly, the J–V–T characteristics of all the fabricated diodes were analyzed with different temperatures (303–423 K). Highlights: High quality WO3 thin films were prepared by sol–gel spin coating technique. Effect of metal dopants (Cd, In and Sn) on structural and optical properties of WO3 thin films were investigated. Microplate-like structure was grown on glass substrates. High-sensitive heterojunction diodes were fabricated. [ABSTRACT FROM AUTHOR]

Inter-connected network grains of tungsten trioxide (WO3) thin films were deposited on glass using a jet nebulizer spray pyrolysis (JNSP) technique by varying the substrate temperature at 350, 400, 450 and 500 °C. Phase transformation (monoclinic to orthorhombic) was observed during the film growth through X-ray diffraction (XRD) analysis. Field emission scanning electron microscope (FE-SEM) images revealed a better grain growth with smooth surface for 400 °C. The WO3 film deposited at 400 °C exhibits minimum band gap and maximum optical conductivity of 3.2 eV and 5.8 × 1014 (Ω.cm)−1. From the current-voltage (I–V) characteristics, the mean electrical conductivity is found to increase gradually and the activation energy reduced at higher substrate temperature. Cu/WO3/p–Si structured Schottky barrier diodes (SBDs) have been fabricated with different substrate temperature and it was tested under variable device temperatures ranging from 30 to 170 °C. The experimental results of all SBDs indicated a linear reduction in the ideality factor (n) with a small increment in effective barrier height (ΦB) with increase in device temperature, which is due to lateral inhomogeneity's at the interface. Moreover, the minimum n value of 2.89 and their corresponding ΦB of 0.71 eV were recorded for device temperature at 170 °C. Compared with other SBDs, the device fabricated at 400 °C demonstrated a better thermal stability and device performance. [ABSTRACT FROM AUTHOR]

The effect of variant high boiling point solvent combinations in the synthesis and photo-sensing characteristics of tin disulfide (SnS2) thin nanosheets were investigated. Solvent dependent single-phase formation was observed by powder X-ray diffractometry (XRD), and results were verified with Raman spectroscopy measurements. Particles synthesized with only oleylamine show a mixed-phase, and two other solvent combinations such as oleylamine + oleic acid + n-octadecene, and oleylamine + oleic acid, show single-phase 2H–SnS2, without phase contamination. Scanning and transmission electron microscopes were used to verify the orbicular and hexagonal shape of synthesized SnS2 nanosheets. Well-characterized samples were employed to fabricate heterojunction photosensitive diodes using a p-type silicon substrate. Light-responsive measurement results of fabricated diodes indicate that the oleylamine + oleic acid synthesized sample show very high light-sensitivity, and the fill factor value of a fabricated diode is closer to the ideal diode. [ABSTRACT FROM AUTHOR]

In this paper, we report the influence of thermal annealing on structural, electrical properties V2O5 thin films and their application of SBD's. V2O5 thin films were prepared using glass substrate by sol gel spin coating technique. Films were annealed at different temperatures such as 300 °C, 400 °C and 500 °C. The prepared films were introduced as an interfacial layer between metal and semiconductor interface. V2O5 films exhibit single phase tetragonal structure and surface morphology interestingly, it was changed into nanorod-like structure at higher annealing temperature which was observed through field emission scanning electron microscopy. Atomic force microscopy reveals the surface roughness and the mentioned roughness is increasing due to the increase of annealing temperature. The elemental composition was confirmed by energy dispersive X-ray spectrum. From UV–Vis absorption spectroscopy results revealed that the band gap shows a decreasing trend on increasing the annealing temperature. Besides, we analyzed the influence of high quality vanadium pentoxide (V2O5) thin films prepared at different annealed temperatures and act as an interfacial layer between metal and semiconductor in the fabrication of Schottky diode. V2O5 films depicts high electrical conductivity (σdc) of 0.945 (S cm−1) with activation energy of 0.0747 eV (Ea) as a function of temperature. The MIS structured Cu/V2O5/n-Si based SBD's diode performance was analyzed for different temperatures ranging from 30 to 150 °C. V2O5 thin-film act as an interfacial layer on Cu/V2O5/n-Si Schottky diode was successfully explained by the thermionic emission theory. [ABSTRACT FROM AUTHOR]

Tungsten disulfide (WS2) thin films were deposited on the glass substrate by varying its temperature from 350 to 500 °C using jet nebulizer spray pyrolysis (JNSP) technique. The WS2 thin films were characterized through various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX), UV-Visible spectroscopy (UV), photoluminescence (PL), Hall measurements and current-voltage (I-V) characteristics. XRD pattern revealed that the prepared WS2 films are polycrystalline in nature with rhombohedral and hexagonal crystal structures. The average crystallite size of WS2 thin films changed from 52.23 to 47.40 nm. SEM images showed the uniform grain size, which is agglomerated at the higher substrate temperature. The presence of elements like W and S was confirmed through EDX spectrum. From UV analysis, the minimum optical band gap and maximum absorption was obtained for the film deposited at 450 °C. The WS2 thin films exhibited an n-type semiconductor nature with the carrier concentration of 1014 cm−3, which was demonstrated through hall measurements. Also, the electrical resistivity of the WS2 films varied from 3.26 × 105 to 1.59 × 107 Ω cm. The p-Si/n-WS2 junction diode was fabricated with various substrate temperature of (350-500 °C). Junction diode parameters like ideality factor (n), barrier height (ϕB) and reverse saturation current (Io) values were calculated and interpreted based on the thermionic emission theory model. [ABSTRACT FROM AUTHOR]

Metal–insulator–semiconductor (MIS) structure of Cu/Zr–WOx/p-Si Schottky diodes with different concentrations (0, 4 and 8 wt%) of Zr content were fabricated. The interfacial layer of zirconium–tungsten oxide (Zr–WOx) film was grown on p-type silicon (p-Si) wafer using jet nebulizer spray pyrolysis (JNSP) technique at the substrate temperature of 400 °C. After that, the Cu electrode was coated on the Zr–WOx film via vacuum deposition method. The multiphase (orthorhombic and cubic) crystal structures of Zr–WOx were revealed by X-ray diffraction (XRD) pattern. The surface morphological analysis using scanning electron microscope (SEM) showed the dissimilar structures of surface and energy dispersive X-ray diffraction (EDX) confirmed the presence of W, Zr and O atoms. Using UV–Visible (UV–Vis) and DC elecrical (I–V) analysis, the minimum band gap energy and average conductivity were obtained for higher concentration (8 wt%) of Zr content. The minimum barrier height (ΦB) and minimum ideality factor (n) values were attained for 4 wt% of Cu/Zr–WOx/p-Si Schottky barrier diode (SBD) under illumination condition. [ABSTRACT FROM AUTHOR]