Influence of N2 flow rate on UV photodetection properties of sputtered p-ZnO/n-Si heterojuctions

Al-N codoped ZnO heterojunction diodes were grown on n-Si (100) substrates using radio frequency (RF) magnetron sputtering with different flow rates of N-2 reactive gas (5-18 sccm). X-ray diffraction results revealed that codoped ZnO thin films have wurtzite structure with crystallite size 25-31 nm. Scanning electron micrographs revealed that all thin film samples have agglomerated flakes type surface morphology. The optical bandgap determined using UV-Vis transmission spectra was found increased with increasing the flow rate of N-2. The current-voltage (I-V) measurements were performed in dark and illumination condition using UV light (wavelength 365 nm) for photodetection application. The high stability and fast switching UV photoresponse behaviour was obtained for p-ZnO/n-Si. The maximum responsivity 0.16 A/W was obtained at 3.2 mW/cm(2) illumination of the UV light (365 nm) at 5 V bias voltage.