Light effect on I-V and profile of C/ω-V and G/ω-V characteristics of In-doped SnO2/Si heterojunction for photodiode applications

The paper deals on heterojunctions (HJ) fabricated onto n type silicon by spray pyrolysis @ 300 degrees C and metallic contacts are fabricated by deposition of silver on SnO2 thin film by thermal evaporation process under low pressure. The ideality factor greater than 3 confirms the non-ideal behavior of the Ag/In:SnO2/Si/Au heterojunction. The series resistance and the height barrier are determined as 2653 Omega and 0.7 V respectively. Using the profile of current voltage (I-V) and capacitance voltage (C-V) characteristics, we determine many electrical parameters like the ideality factor, the barrier height, the series resistance, and the saturation current, both in dark and light conditions. Besides HJ presents a high rectification ratio, and the interface density with and without R-s reached a minor value of 3 x 10(12) (eVxcm(2))(-1) at 0.55 eV. The C-V characteristics are strongly frequency dependent within the reverse bias range which makes it p-type semiconductor. 3D scanned AFM showed the nanostructured aspect of the oxide layer. Decrease of C/omega-V and G/omega-V characteristics are well discussed within the 100 kHz-1 MHz frequency range.