Fabrication and Emission Properties of a n-ZnO/p-GaN Heterojunction Light-Emitting Diode

报道了n-ZnO/p-GaN异质结构发光二极管的制备及其发光特性.采用金属有机气相外延技术在Mg掺杂p型GaN衬底上外延n型ZnO薄膜以形成p-n结.实验发现在一定配比的HF酸和NH4Cl溶液中,腐蚀深度和腐蚀时间呈线性关系,并且二氧化硅和ZnO的腐蚀速率得到很好的控制,这对器件制备的可靠性非常重要.电流-电压(I-V)特性测试显示该器件结构具有明显的整流特性.室温下,在正反向偏压状态下都可用肉眼观察到电致发光现象.同时,通过与光致发光谱进行比较,对电致发光谱中发光峰的起源和发光机制进行了探讨.

Fabrication and Emission Properties of a n-ZnO/p-GaN Heterojunction Light-Emitting Diode

We report the fabrication and characterization of light-emitting diodes based on n-ZnO/p-GaN heterojunctions.The n-type ZnO epilayer is deposited by metalorganic chemical vapor deposition (MOCVD) on a MOCVD grown Mg-doped p-GaN layer to form a p-n heterojunction.During the etching process, the relation between the etching depth and the etching time is linear in a HF and NH_4Cl solution of a certain ratio.The etching rates of the SiO_2 and ZnO are well controlled,which are essential for device fabrication.The current-voltage relationship of this heterojunction shows a diode-like rectifying behavior.In contrast to previous reports,electroluminescence (EL) emissions are observed by the naked eye at room temperature from the n-ZnO/p-GaN heterojunction under forward-and reverse-bias.The origins of these EL emissions are discussed in comparison with the photoluminescence spectra.