UV/vis range photodetectors based on thin film ALD grown ZnO/Si heterojunction diodes

We present ultraviolet-visible (UV/vis) range photodetectors (PDs) based on thin film ZnO (n)/Si (p) heterojunction diodes. ZnO films are grown by the atomic layer deposition (ALD) technique at growth temperatures of 80, 150, 200 and 250 degrees C. The fabricated ZnO (n)/Si (p) photodetectors (ZnO-Si-PDs) show good electrical rectification characteristics with ON/OFF ratios reaching up to 10(3). Under UV (350 nm wavelength) and visible (475 nm wavelength) light illumination, the ZnO-Si-PDs give photoresponsivity values of 30-37 mA W-1 and 74-80 mA W-1 at 0.5 V reverse bias, respectively. Photoluminescence (PL) spectra of ALD grown ZnO thin films are used to support the results.