Optical interactions in the InSe/CdSe interface

Abstract

In this work, the structural and optical properties of the InSe/ CdSe heterojunction are investigated by means of X-ray diffraction and ultraviolet-visible light spectrophotometry techniques. The hexagonal CdSe films that were deposited onto amorphous InSe and onto glass substrates at a vacuum pressure of 10 À5 mbar, exhibited interesting optical characteristics. Namely, the absorption, transmission, and reflection spectra that were recorded in the incident light wavelength range of 300-1100 nm, for the InSe, CdSe, and InSe/CdSe interface revealed direct allowed transition energy bandgaps of 1.44, 1.85, and 1.52 eV, respectively. The valence-band offset for the interface is found to be 0.36 eV. On the other hand, the dielectric constant spectral analysis displayed a large increase in the real part of the dielectric constant associated with decreasing frequency below 500 THz. In addition, the optical conductivity spectra that were analyzed and modeled in accordance with the Drude theory displayed a free-carrier average scattering time of 0.4 fs and a drift mobility of 6.65 cm 2 V À1 s À1 for the InSe/CdSe interface. The features of this interface nominate it as a promising member for the production of optoelectronic Schottky channels and as thinfilm transistors. 1 Introduction Owing to the remarkable optical properties they exhibit [1][2][3][4][5][6][7], the cadmium selenide and InSe thin films are attractive materials in optoelectronic technology. The quantum dot-sensitized solar cells (QDSCs) of CdSe displayed high power conversion efficiency of 3.26 AE 0.10% under one sun illumination [2]. In addition, the ZnTe/CdSe QD-based QDSCs showed a champion power conversion efficiency of 7.17% and an efficiency of 6.82% under one full sun illumination [3]. Moreover, the CdTe/ CdSe nanocrystal (NC) solar cells with the inverted structure (ITO/ZnO/CdSe/CdTe/Au) that had been fabricated by the simple solution process coupled with the layer-by-layer sintering technique displayed an annealing strategydependent device performance [4]. The efficiency of these NC devices reached 5.81% at an annealing temperature of 340 8C. Furthermore, very small size (3-5 nm) particles of zinc-blende cadmium selenide nanocrystals modified with oleic acid showed an NC solar cell efficiency of $1.08% [5]. The most beneficial property of the last two types is the ability of preparation from solutions.On the other hand, the n-InSe/p-Si heterojunction is reported to exhibit a photovoltaic characteristic with a

Nonlinear optical performance of CdO/InSe Interfaces

“…The features of the CdO/InSe indicate it is applicability as optical media with relatively mobile charge carriers compared to other heterojunction devices that are based on InSe. As for examples for the InSe/CdSe interfaces [22], the drift mobility being 6.65 / cm Vs 2 was lower than that we achieve when we used CdO instead of CdSe. The free carrier concentration is also two magnitudes of order lower in CdO/InSe than that in InSe/ CdSe.…”

“…) for the CdO/InSe interfaces as 0.106m o assuming m CdO * = 0.33m o [24] and InSe * = 0.156m o [22], it was possible to determine the optical conduction parameters for the interface. The optical conductivity parameters are shown in The plasmon frequency for this oscillator is ∼100 MHz.…”

Band Offsets, Optical Conduction, and Microwave Band Filtering Characteristics of γ‐In2Se3/CuO Heterojunctions

“…Comparing the performance of the for γ ‐In 2 Se 3 /CuO heterojunctions with the previously reported InSe/CdSe system, [ 33 ] due to the values of optical conductivity parameters, it is possible to predict that the coating of indium selenide with CuO is better than coating with CdSe. While the InSe/CdSe reveal drift mobility value of 6.65 cm 2 Vs −1 , that of γ ‐In 2 Se 3 /CuO show value of ≈31 cm 2 Vs −1 .…”