Enhancement of performance CdxPb1-xS / porous silicon heterojunction photodetector by chemical spray pyrolysis method

This work investigates the photodetector characteristics of lead and cadmium sulfide thin films deposited on porous silicon heterojunction at composites (x=0,0.25,0.5,0.75,1). The characteristics of all deposited samples were estimated by X-ray diffraction (XRD), highresolution scanning electron microscope (FESEM), Energy-dispersive X-ray (EDX), I-V measurements, and photodetector properties. PbS and CdS thin films have been successful, and photodetector properties on the porous silicon surface have performed well using the chemical spray method. An X-ray confirmed that the prepared samples have a crystalline phase structure. Besides, the results indicate that the PbS and CdS thin films have cubic and hexagonal structures respectively. In detail, the crystalline size decreases with increasing concentration. FESEM images show that the porous silicon has a sponge-like structure and is uniformly distributed at the surface. Furthermore, I-V curves of the prepared thin films have rectifying behavior. The performance of CdxPb1–xS/ Porous silicon as a photodetector shows that the maximum values of quantum efficiency were found to be 10%, 14%, 16%, 23%, and 44% at x=0,0.25,0.5, 0.75and 1 respectively. The variation of photocurrent with time (time rise and time fall) has good electrical stability and fast response under light cycling. The photodetector performance of CdxPb1–xS/ Porous silicon heterojunction is in a positive linear relationship with the used concentration.