Tunable charge transport through n-ZnO nanorods on Au coated macroporous p-Si

Abstract

We report a strategy to synthesize patterned n-ZnO nanorods on Au coated macroporous p-Si. Electric field assisted growth of ZnO under UV exposure results in the formation of well-aligned and relatively defect-free n-ZnO nanorods on the macroporous Si-template. The luminescence characteristics of ZnO exhibit a single Gaussian peak due to band-to-band transition in ZnO. Temperature dependent electrical transport through the n-ZnO/Au/p-Si heterojunction reveals unusual characteristics. Under forward bias, the I–V plots are diode-like with a remarkably low turn-on voltage and significantly high forward bias current. The non-linear forward current decreases appreciably with temperature while the reverse bias current is linear and is almost temperature independent. The Au layer present between the n-ZnO and p-Si significantly modifies the junction and allows tuning the device characteristics from diode-like to ohmic under different biasing conditions.