Open Access Nano Express

n-ZnO nanorods/p+-Si (111) heterojunction light emitting diodes

Jenn Kai Tsai*, Jun Hong Shih, Tian Chiuan Wu and Teen Hang Meen

Author affiliations

Department of Electronic Engineering, National Formosa University, Yunlin, 632, Taiwan

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Citation and License

Nanoscale Research Letters 2012, 7:664  doi:10.1186/1556-276X-7-664

Published: 6 December 2012

Abstract

In this study, we report the effects of thermal annealing in nitrogen ambient on the optical and electrical properties of zinc oxide (ZnO) nanorod (NR) arrays for the application in light emission diodes (LED). The single-crystalline ZnO NR array was synthesized on p+-Si (111) substrate without seed layer using simple, low-cost, and low-temperature hydrothermal method. The substrate surface was functionalized by hydrofluoric acid and self-assembled monolayer of octadecyltrimethoxysilane ((CH3 (CH2)17Si(OCH3)3). ZnO NRs were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and micro-photoluminescence (micro-PL). The results of FESEM and XRD indicate that single crystalline ZnO NRs with (002) preferred orientation along the substrate surface is successfully grown on functionalized p+-Si (111) substrate. The current–voltage and electroluminescence (EL) characteristics of the LED show that the most suitable annealing temperature ranges from 400°C to 600°C. Both PL and EL spectra show broadband emissions, ultraviolet and visible (green-yellow) light. The white-like light emission is able to be observed by naked eyes.

Keywords:
ZnO; Nanorods; Hydrothernal method; Heterojunction; LED; Seed layer free