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The main aim of this article has to investigate some electro-optical properties of MoS2/p-Si heterojunctions fabricated by an innovative technique, AJP. For this purpose, MoS2 thin films of different thicknesses were deposited on corning glass and p-type Si substrates by using RF magnetron sputtering. The structural, morphological and optical properties of MoS2 films were analyzed by different characterization techniques. In addition, the electrical properties of heterojunction devices of MoS2/p-Si were examined by I-V measurements. Depending on the film thickness, localized states in the band gap region, which are explained by Urbach energy, electron–phonon interaction and steepness parameter analyses, were considered to be effective on device performance. It was observed that the fabricated MoS2/p-Si device with a thickness of 10 nm exhibited a higher rectification ratio and photovoltaic outputs. According to the obtained results, this study offers a new way to make better the performance of electro-optical devices based on MoS2. [ABSTRACT FROM AUTHOR]

In this work, we reported the effect of different metal contacts on performance of metal–oxide–semiconductor (MOS)-structured Schottky diodes formed with the vanadium pentoxide thin film (V2O5) interfacial layer. V2O5 thin films were deposited by radio frequency (RF) magnetron sputtering on n-type silicon (n-Si) and Corning glass (CG) substrates at room temperature. Then, the obtained films were annealed at 300 °C and 500 °C. The effects of annealing temperature on physical properties of the films were investigated by X-ray photoelectron spectroscopy, secondary ion mass spectroscopy, atomic force microscopy, UV–Vis spectroscopy, and photoluminescence. The MOS-structured Al/V2O5/n-Si, Ti/V2O5/n-Si and Au/V2O5/n-Si Schottky barrier diodes (SBDs) performance was analyzed with I–V measurements at room temperature. The Schottky diodes were compared with each other according to three methods (Classic, Norde and Cheung). The experimental results indicated that the Schottky diode produced with Al contact had better performance than the others. [ABSTRACT FROM AUTHOR]

Summary: Cu2ZnSnSe4 and Cu2ZnSn(S,Se)4 absorber films were grown on soda lime glass and Mo‐coated soda lime glass substrates by deposition of the precursor films via RF magnetron sputtering method in the stacking orders of Cu/Sn/Zn/Mo/SLG and Cu/Sn/ZnS/Mo/SLG using metallic Zn or binary sulfide ZnS targets and subsequently carrying out of selenization process. It was aimed to find out the effect of Zn or ZnS target types and the small amount of S originated from ZnS target material used in the deposition of precursor films on the structural, morphological, optical, and electrical characteristics of the films to be selenized. XRD and Raman spectroscopy analysis showed that the kesterite CZTSe structure was predominantly formed in both cases where Zn and ZnS targets were used. According to the EDX analysis, S content in the prepared film using ZnS target was only around 1.79 at%. This indicated that a considerable amount of S in the film was driven out during the selenization process. Scanning electron microscopy analysis revealed that ZnS target material contributed to the achievement of the absorber films with larger grain size. It was also determined that the thickness of the interfacial MoSe2 film between the absorber and Mo films decreased by using ZnS target in the precursor film. This was attributed to ZnS layer with a high melting point acting as a barrier layer over Mo film and retarding the diffusion of Se into the Mo film during the selenization process. In addition, the band gap energy values of the Cu2ZnSnSe4 and Cu2ZnSn(S,Se)4 films were found to be 1.18 and 1.28 eV, respectively. [ABSTRACT FROM AUTHOR]

The TiO2/SiO2 film being the dielectric layer was grown on the n-Si wafer using radio frequency (RF) magnetron sputtering. Thus, the Au/TiO2/SiO2/n-Si metal-oxide-semiconductor (MOS) capacitor was fabricated with the forming of metal contacts. The optical properties of the oxide film were analyzed by Fourier transform infrared (FTIR) and Ultraviolet-visible (UV-Vis) spectroscopy. The electrical properties of the MOS capacitor were investigated using admittance (Y = G + iωC) measurements performed at various frequencies. The series resistance (Rs) parameter of the capacitor was derived from the conductance method. [ABSTRACT FROM AUTHOR]

Vanadium pentoxide (V2O5) thin films were grown by radio frequency magnetron sputtering on n-type silicon (n-Si) and glass substrates at 500 °C. V2O5 thin films were deposited with various thicknesses (100–400 nm). The effect of film thickness on the physical properties of the films was systematically investigated by different characterization techniques. The structural, morphological, optical and carrier properties of the samples were characterized using various techniques. All of the obtained films were found to have an orthorhombic structure and preferred orientation along (001) plane. The band gap energy values of the films were found to be in the range from 2.23 to 2.50 eV, and their optical transmittance were in the range from 20 to 80% in the visible region. With increasing film thickness, it was seen that the surface roughness increased and the resistivity decreased. Then, electrical parameters of the Ti/V2O5 Schottky diode fabricated on n-Si substrate by the sputtering system were presented at the room temperature. The obtained experimental results showed that the deposited V2O5 films can be used in electro-optical applications. [ABSTRACT FROM AUTHOR]

In the present study, we reported the results of the investigation of electrical and optical measurements in AlxGa1-xN/GaN heterostructures (x=0.20) that were grown by way of metal-organic chemical vapor deposition on sapphire and SiC substrates with the same buffer structures and similar conditions. We investigated the substrate material effects on the electrical and optical properties of Al0.20Ga0.80N/GaN heterostructures. The related electrical and optical properties of AlxGa1-xN/GaN heterostructures were investigated by variable-temperature Hall effect measurements, photoluminescence (PL), photocurrent, and persistent photoconductivity (PPC) that in turn illuminated the samples with a blue (λ=470 nm) light-emitting diode (LED) and thereby induced a persistent increase in the carrier density and two-dimensional electron gas (2DEG) electron mobility. In sample A (Al0.20Ga0.80N/GaN/sapphire), the carrier density increased from 7.59×1012 to 9.9×1012 cm-2 via illumination at 30 K. On the other hand, in sample B (Al0.20Ga0.80N/GaN/SiC), the increments in the carrier density were larger than those in sample A, in which it increased from 7.62×1012 to 1.23×1013 cm-2 at the same temperature. The 2DEG mobility increased from 1.22×104 to 1.37×104 cm-2/V s for samples A and B, in which 2DEG mobility increments occurred from 3.83×103 to 5.47×103 cm-2/V s at 30 K. The PL results show that the samples possessed a strong near-band-edge exciton luminescence line at around 3.44 and 3.43 eV for samples A and B, respectively. The samples showed a broad yellow band spreading from 1.80 to 2.60 eV with a peak maximum at 2.25 eV with a ratio of a near-band-edge excitation peak intensity up to a deep-level emission peak intensity ratio that were equal to 3 and 1.8 for samples A and B, respectively. Both of the samples that were illuminated with three different energy photon PPC decay behaviors can be well described by a stretched-exponential function and relaxation time constant τ as well as a decay exponent β that changes with the substrate type. The energy barrier for the capture of electrons in the 2DEG channel via the deep-level impurities (DX-like centers) in AlGaN for the Al0.20Ga0.80N/GaN/sapphire and Al0.20Ga0.80N/GaN/SiC heterojunction samples are 343 and 228 meV, respectively. The activation energy for the thermal capture of an electron by the defects ΔE changed with the substrate materials. Our results show that the substrate material strongly affects the electrical and optical properties of Al0.20Ga0.80N/GaN heterostructures. These results can be explained with the differing degrees of the lattice mismatch between the grown layers and substrates. [ABSTRACT FROM AUTHOR]

A temperature dependent forward-bias current-voltage (I-V) characteristics in the temperature range of 80-410 K was used to study the current-transport mechanisms in (Ni/Au)-[Al.sub.0.22][Ga.sub.0.78]N/AlN/GaN heterostructures. The results revealed that the mechanism of charge transport in the (Ni/Au)-[Al.sub.0.22][Ga.sub.0.78]N/AlN/GaN heterostructure in the temperature range of 80-410 K could be performed by tunneling among those dislocations intersecting the space charge region.

The transport properties of high quality AlGaN/AlN/GaN and AlInN/AlN/GaN heterostructures are examined and compared by using temperature dependent Hall effect measurements. The studies have suggested that the AlInN/AlN/GaN high electron mobility transistor (HEMT) structure after optimization of the growth and design parameters might display better transformance performance when compared with AlAGaN/GaN based HEMTs.

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Abstract: In this work, continuous and conductive ultrathin Ag films with highly infrared reflective and highly visible transmittance were achieved using several metal seeds (Ti, Nb, Cr, Ni, Mo, Pt, Cu, and Ru), having ~1‐2 nm in thickness, deposited between Ag and dielectric AZO layers on glass substrate by magnetron sputtering with confocal target geometry. The optical properties in the visible and infrared ranges and conductivity of Ag/M‐seed/AZO/glass structures were compared in order to determine the influence of the seeds. It was observed that all M‐Seeds increased both visible transmittance and infrared reflectance. But also, it was shown that Nb and Ti seed layers which help on coalesced of Ag and AZO layers are more effective on the electro‐optical characteristics of the Ag thin films than the other seeds. Ag/Nb/AZO/glass and Ag/Ti/AZO/glass structures showed 2.81 and 2.84 Ω / □ sheet resistance and low surface roughness, respectively, which are the best film structures. In addition, these films have homogeneous and defect‐free surfaces that do not cause any electrical breakdown. Besides, Nb and Ti seeded structures have the low‐emissivity both 780‐2500 nm and long wavelength (λ  >  3 μm) spectral region as 0.0357 and 0.0361, respectively. [ABSTRACT FROM AUTHOR]