Band Offsets, Dielectric Dispersion, Optical Conduction and Impedance Spectroscopy Analyses of WO3/Ga2S3 Heterojunctions

Abstract

Stacked layers of amorphous WO3 and Ga2S3 are fabricated by the thermal evaporation technique under a vacuum pressure of 10–5 mbar. The structural, compositional, optical, dielectric and electrical properties of the WO3/Ga2S3 (WG) heterojunctions are investigated. It is observed that the WG heterojunctions exhibit well-aligned conduction bands. The valance band offsets are 0.58 eV. In addition, as a dielectric resonator, WG interfaces displayed single infrared oscillator, double ultraviolet (UV) oscillators and triple visible light oscillators. The optical conductivity modeling by the Drude–Lorentz approach has shown that for these oscillators the drift mobility of charge carriers is 7.52, 9.40 and 18.80 cm2/Vs, respectively. The optical conductivity in the ultraviolet range is very high nominating the WG interfaces for UV sensing. On the other hand, the impedance spectroscopy analysis for the Yb/WG/C interfaces revealed the wide tunability of the devices when employed as capacitors and as bandpass filters. The WG interfaces can perform as radiowave/microwave band filters. The microwave cutoff frequency for the devices reaches ~ 1.96 GHz when the propagating AC signal is fixed at frequency of 1.19 GHz.