Investigation on spectroscopic and electrical properties of p-Si/CdS_xSe_1−x (0≤ x ≤1) heterostructures for photodetector applications

CdS_xSe_1−x (0 ≤ x ≤ 1) films were deposited on p-Si via thermal co-evaporation method with CdS and CdSe as source materials. The heterostructures were studied for their structural, spectroscopic and electrical behaviours by using X-ray diffraction, photoluminescence spectroscopy, low temperature Raman spectroscopy and I-V characterization. Systematic shift in the diffraction peak has confirmed the composition modulation and presence of mixed phase in the ternary CdSSe. Temperature dependent Raman study showed that longitudinal optical modes are shifted to higher wavenumber, which is ascribed to variation in strain and lattice constants with temperature. The diode parameters including ideality factor and barrier height were extracted by applying various models to the temperature dependent I-V measurements. The spectral response of p-Si/CdS_xSe_1−x (0 ≤ x ≤ 1) were analysed and the heterostructure with x = 0.2 showed high response confirming the device suitability of the heterostructures.