Fabrication and characterization of ZnO nanowires based UV photodiodes

A heterojunction of n-type zinc oxide (ZnO) nanowires and p-type silicon has been successfully constructed to demonstrate ultraviolet (UV) photodiodes. The prototype device consists of naturally doped n-type ZnO nanowites grown on top of a (100) p-silicon substrate by the bottom-up growth process. The diameter of the nanowires is in the range of 70-120 nm, and the length is controlled by the growth time. The isolation is achieved by using spin-on glass (SOG) that also works as the foundation of the top electrode. The current-voltage (I-V) characteristics show the typical rectifying behavior of heterojunctions, and the photodiode exhibits response of similar to 0.07A/W for UV light (365 nm) under a 20 V reverse bias. (c) 2005 Elsevier B.V. All rights reserved.