Search

Gas sensing properties of metal oxide semiconductors draw high attention due to their simple fabricating methods, and low cost, chemical, and physical properties. In general, a high bandgap (>2 eV) can cause them to react in the UV region through the electromagnetic spectrum. Controlling the UV-photodetection and gas sensing ability of MoO2-MoO3 thin film through tungsten (W) doping of different ratios have been reported here. The preparation of these films was grown using a reactive magnetron sputtering system with different power sputtering of W-content. The bandgap calculations showed that the samples have a wide bandgap value. A small particle size of 8nm was observed through high W doping concentration which enhanced these materials toward high efficient gas sensing and UV photodetector applications. The UV optical sensor exhibits a high responsivity value of 2500A/W and an external quantum efficiency (EQE) value of 5x109 at 365nm. Also, an increase in the photocurrent gain value with increasing the W amount with a maximum value of 0.13, while a photocurrent of 1mA was observed. On the other hand, a fast-response/recovery time-based CO2 gas sensor of less than 10 sec was observed. The thin-film sensors showed well-defined adsorption and desorption kinetics in a CO2 environment with a p-type chemisorption behavior., Metal oksit yarı iletkenlerin gaz algılama özellikleri, basit üretim yöntemleri ve düşük maliyeti, kimyasal ve fiziksel özellikleri nedeniyle büyük ilgi görmektedir. Genel olarak, yüksek bir bant aralığı (>2 eV), elektromanyetik spektrum yoluyla UV bölgesinde reaksiyona girmelerine neden olabilir. Farklı oranlarda tungsten (W) dopingi yoluyla MoO2-MoO3 ince filmin UV foto algılama ve gaz algılama yeteneğinin kontrol edilmesi burada rapor edilmiştir. Bu filmlerin hazırlanması, W içeriğinin farklı güç püskürtmeli reaktif magnetron püskürtme sistemi kullanılarak büyütüldü. Bant aralığı hesaplamaları, örneklerin geniş bir bant aralığı değerine sahip olduğunu göstermiştir. Bu malzemeleri yüksek verimli gaz algılama ve UV fotodetektör uygulamalarına doğru geliştiren yüksek W katkı konsantrasyonu yoluyla 8 nm'lik küçük bir parçacık boyutu gözlemlendi. UV optik sensör, 365nm'de 2500A/W'lik yüksek bir duyarlılık değeri ve 5x109'luk bir harici kuantum verimliliği (EQE) değeri sergiler. Ayrıca, 1mA'lık bir fotoakım olurken, maksimum 0.13 değerinde W miktarı arttıkça fotoakım kazanç değerinde bir artış gözlemlendi. Öte yandan, 10 saniyeden kısa bir hızlı yanıt/kurtarma süresine dayalı CO2 gaz sensörü gözlendi. İnce film sensörleri, p-tipi kimyasal adsorpsiyon davranışına sahip bir CO2 ortamında iyi tanımlanmış adsorpsiyon ve desorpsiyon kinetiği gösterdi.

This study was on the optoelectronic properties of multilayered two-dimensional MoS

Ultrathin MoO3 semiconductor nanostructures have garnered significant interest as a promising nanomaterial for transparent nano- and optoelectronics, owing to their exceptional reactivity. Due to the shortage of knowledge about the electronic and optoelectronic properties of MoO3/n-Si via an ALD system of few nanometers, we utilized the preparation of an ultrathin MoO3 film at temperatures of 100, 150, 200, and 250 °C. The effect of the depositing temperatures on using bis(tbutylimido)bis(dimethylamino)molybdenum (VI) as a molybdenum source for highly stable UV photodetectors were reported. The ON–OFF and the photodetector dynamic behaviors of these samples under different applied voltages of 0, 0.5, 1, 2, 3, 4, and 5 V were collected. This study shows that the ultrasmooth and homogenous films of less than a 0.30 nm roughness deposited at 200 °C were used efficiently for high-performance UV photodetector behaviors with a high sheet carrier concentration of 7.6 × 1010 cm−2 and external quantum efficiency of 1.72 × 1011. The electronic parameters were analyzed based on thermionic emission theory, where Cheung and Nord’s methods were utilized to determine the photodetector electronic parameters, such as the ideality factor (n), barrier height (Φ0), and series resistance (Rs). The n-factor values were higher in the low voltage region of the I–V diagram, potentially due to series resistance causing a voltage drop across the interfacial thin film and charge accumulation at the interface states between the MoO3 and Si surfaces.

The aim of this research is to analyze the influence of various factors on the photo-ionization cross-section in (Al, Ga)N/AlN double triangular quantum wells. Using the finite difference method, the effects of the electric field, hydrostatic pressure, temperature, and Ga concentration were investigated within the effective mass and parabolic approximations. Our findings show that the photo-ionization cross-section (PICS) is highly dependent on all the variables under consideration. The optical spectra were blue-shifted with increasing electric field and pressure and red-shifted with increasing temperature and impurity displacement far from the center of the structure. Furthermore, it was found that changes in gallium content and impurity position can increase the PICS amplitude. A comparison of the obtained results with the existing literature as a limiting case of the reported problem is also provided, and excellent agreement is found.

The application of the photonic superlattice in advanced photonics has become a demanding field, especially for two-dimensional and strongly correlated oxides. Because it experiences an abrupt metal–insulator transition near ambient temperature, where the electrical resistivity varies by orders of magnitude, vanadium oxide (VO2) shows potential as a building block for infrared switching and sensing devices. We reported a first principle study of superlattice structures of VO2 as a strongly correlated phase transition material and tungsten diselenide (WSe2) as a two-dimensional transition metal dichalcogenide layer. Based on first-principles calculations, we exploit the effect of semiconductor monoclinic and metallic tetragonal state of VO2 with WSe2 in a photonic superlattices structure through the near and mid-infrared (NIR–MIR) thermochromic phase transition regions. By increasing the thickness of the VO2 layer, the photonic bandgap (PhB) gets red-shifted. We observed linear dependence of the PhB width on the VO2 thickness. For the monoclinic case of VO2, the number of the forbidden bands increase with the number of layers of WSe2. New forbidden gaps are preferred to appear at a slight angle of incidence, and the wider one can predominate at larger angles. We presented an efficient way to control the flow of the NIR–MIR in both summer and winter environments for phase transition and photonic thermochromic applications. This study’s findings may help understand vanadium oxide’s role in tunable photonic superlattice for infrared switchable devices and optical filters.