The level of silicon p-i-n photodiodes responsivity depending on thickness of the chromium sublayer on the back side of the device crystal, which is deposited to improve adhesion of gold, was studied. Transmission spectra of the chromiumfilm at its different thicknesses were obtained. It was found that starting from the sublayer thickness of 17 nm and less, the transmittance changes by one percent, which does not lead to an increase in photoresponsivity with a further decrease in the thickness of chromium.
The I-V and C-V–characteristics of the isotype Zn1-xCoxO/n-GaP heterojunction fabricated by spray pyrolysis of Zn1-xCoxO thin films on n-GaP crystalline substrates have been investigated and analyzed. The mechanisms of electron tunneling through the energy barrier of the heterojunction at forward and reverse currents and the conditions of generating reverse current are analyzed. The dynamics of changes in the capacitive parameters of Zn1-xCoxO thin film based on the C-V–characteristics is established. The photoelectric properties of the heterostructure are analyzed.
The transmission spectra of ZnO:Al films and I-V-characteristic of the isotype heterojunction ZnO:Al/n-Si fabricated by the method of RF magnetron sputtering of thin ZnO:Al films onto n-Si crystalline substrates were investigated and analyzed. The mechanisms of electron tunneling through the energy barrier of the heterojunction at forward and reverse biases are analyzed. The influence of temperature on the parameters of the heterojunction is determined. The photoelectric properties of the heterostructure are analyzed.
The results of investigation of optical and electrical properties of p-Cu2FeSnS4 thin polycrystalline films obtained by spray pyrolysis of aqueous solutions of salts of CuCl2∙2H2O, FeCl3∙6H2O and SnCl4∙5H2O and (NH2)2CS are presented. On the basis of the analysis of the light absorption spectra, the optical band gap of the films Eg ≈ 1.72 eV was determined and the dynamics of its change during thermal treatment under low vacuum conditions (0.1 Pa). The conductivity activation energies (Ea = 0.75 eV) and the height of the energy barriers between the grain boundaries (Eb = 0.07 eV) are determined from the temperature dependences of the electrical conductivity.
The results of investigation of optical and electrical properties of thin films of р-(3ZnTe)0.5(In2Te3)0.5 obtained by thermal evaporation and heterostructures based on them are presented in the paper. On the basis of the analysis of the spectra of light absorption, the optical width of the band gap and its dependence on the sputtering mode is determined. The heterostructures of n-Si/p-(3ZnTe)0.5(In2Te3)0.5 and n-CdTe/p-(3ZnTe)0.5(In2Te3)0.5 were obtained and they have straightening properties. Based on the analysis of the temperature dependences of the I-V characteristics, the presence of a tunneling mechanism of electron motion at forward and reverse bias through the energy barrier of the heterojunction is established.
The conditions for the production of rectifying heterostructures p-Сu2ZnSnSe4/n-CdTe by the method of RF-magnetron sputtering of Сu2ZnSnSe4 films onto crystalline substrates n-CdTe were investigated. Mechanisms of forming direct and reverse currents through the heterojunction were set based on the analysis of temperature dependences of I-V characteristics. It is established that the heterostructure generates idle voltage VOC = 0.42 V, short-circuit current ISC = 0.175 mA/cm2 and the fill factor FF = 0.4 when illuminated at 80 mW/cm2.
p-NiO/n-CdTe-photosensitive heterojunctions were prepared by the deposition of nickel oxide thin films onto n-type single-crystal CdTe substrates by DC reactive magnetron sputtering. The analysis of capacitance-voltage (C−V) characteristics, measured at different frequencies of the small amplitude AC signal and corrected by the effect of the series resistance, provided evidence of the presence of electrically charged interface states, which significantly affect the measured capacitance. The dominant current transport mechanisms in the heterojunctions were determined at forward and reverse biases. Using “light” I−V characteristics, we determined the open-circuit voltage Voc=0.42 V, the short-circuit current Isc=57.5 μA/cm2, and the fill factor FF=0.24 under white light illumination with the intensity of 80 mW/cm2.
The present paper analyzes the сharge transport mechanisms and spectrometric properties of In/CdTe/MoOx heterojunctions prepared by magnetron sputtering of indium and molybdenum oxide thin films onto semi-insulating p-type single-crystal CdTe semiconductor, produced by Acrorad Co. Ltd. Current-voltage characteristics of the detectors at different temperatures were investigated. The charge transport mechanisms in the heterostructures under investigation were determined: the generation-recombination in the space charge region (SCR) at relatively low voltages and the space charge limited currents at high voltages. The spectra of 137Cs and 241Am isotopes taken at different applied bias voltages are presented. It is shown that the In/CdTe/MoOx structures can be used as X/γ-ray detectors in the spectrometric mode.
The investigation influence of selenium on the optical properties of thin films KZTS(Se) was carried out on spectrometer SF-2000 within the interval of wavelengths λ = 0.2 ÷ 1.1 μm. For measuring R attachment Pike was used. Basing on the dependencies α2 on the energy of incident electromagnetic radiation it was determined that in films the direct allowed interband optical transitions occur, and the value of the band gap was obtained.
Graphite/n-SiC Shottky diodes were prepared by means of the recently proposed technique based on the transferring of drawn graphite films onto the n-SiC single crystal substrate. Current-voltage characteristics were measured and analyzed. High quality ohmic contancts were prepared by the DC magnetron sputtering of Ni thin films onto cleaved n-type SiC single crystal substrates. The height of the potential barrier and the series resistance of the graphite/n-SiC junctions were measured and analysed. The dominant current transport mechanisms through the diodes were determined. There was shown that the dominant current transport mechanisms through the graphite/n-SiC Shottky diodes were the multi-step tunnel-recombination at forward bias and the tunnelling mechanisms at reverse bias.
Structure and optical properties of thin films cadmium CZTS produced by RF magnetron sputtering of preliminarily synthesized material are studied. Transmission and reflection coefficients are studied in a range from 0.4 to 4.0 μm. On the basis of the experiments of transmission and reflection coefficients the index of refraction and optical width of the bandgap of thin films under study are measured by the method based on measuring of the transmission and reflection coefficients. It was found out that there are direct interzone optical transitions in the thin films under study.
Optical properties of thin films cadmium chalcogenide produced by RF magnetron sputtering of preliminarily synthesized material are studied. Transmission and reflection coefficients are studied in a range from 0.4 to 1.1 μm. On the basis of the experiments of transmission and reflection coefficients the index of refraction and optical width of the bandgap of thin films under study are measured by the Swanepoel's method аnd method based on measuring of the transmission and reflection coefficients. It was found out that there are direct interzone optical transitions in the thin films under study.
This paper reports optical properties of n-type SnS2 thin films, prepared by spin-coating of a sol-gel based on the lowcost and environmentally friendly solvent dimethyl sulfoxide (DMSO). The effect of a short-term low-temperature treatment in air and final annealing under low vacuum (0.1 Pa) on the synthesis of tin disulfide films was tested and analyzed. The dynamics of changes of optical properties of the films on the parameters of spin-coating and heat treatment was established. The value of the band gap Eg ≈ 2.25 – 2.54 eV for SnS2 and Eg ≈ 1.99 eV for Sn2S3 was determined from the analysis of optical characteristics.
The investigation was carried out on the wavelengths interval of 0.9≤λ≤26.6 μm. Basing on the dependencies α2 on the energy of incident electromagnetic radiation it was determined that in crystals the direct allowed interband optical transitions occur, and the value of the band gap was obtained. Of our research follows that these crystals can be used for the manufacture of optical filters.
The values of refraction index, the main reflection index and reflection coefficient for the investigated crystals were
determined on the basis of the study of reflection and transmission coefficients of (3HgSe)0.5(In2Se3)0.5 crystals doped
with Mn or Fe. The investigation was carried out on the wavelengths interval of 0.9≤λ≤26.6 μm. Basing on the
dependencies α2 on the energy of incident electromagnetic radiation it was determined that in crystals the direct allowed
interband optical transitions occur, and the value of the band gap was obtained. The influence of temperature on the
optical transmittance has been studied in the interval of 120-300 K.
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