Achievement of high infrared photoresponse in n-MoO3/p-Si heterostructure photodiode prepared via the thermal oxidation method, the influence of oxygen flow rate

Abstract

For the first time, the molybdenum oxide (MoO3) thin films were deposited on a p-type Si substrate to create a heterojunction infrared (IR) photodiode via the simple thermal oxidation technique, while the oxygen flow rate was varied from 20 to 80 sccm. The XRD diffractograms confirmed the formation of an orthorhombic structure (α-MoO3 phase) in all the synthesized layers, consistent with their Raman spectra. The FESEM images showed that the prepared samples have similar flat flakes on top and nano-spherical particles underneath with a thickness of 220 ± 20 nm. The current density-voltage (J-V) measurements showed that with increasing O2 flow rate, the overall rectification ratio (IF/IR) of the samples is increased, with a maximum of 43.60 for the one fabricated at 60 sccm O2 flow rate. Also compared to other layers, this sample with the highest oxygen vacancies, i.e., MoO2.84, showed this property led this sample to achieve the highest photoresponse ratio (ILight/IDark) of 17 to the 835 nm IR radiation.