用于氮化镓发光二极管窗口层的铝掺杂氧化锌的生长

因应新时代电子产品的需求,透明导电薄膜(Transparent Conductive Oxides,TCO)的应用也更加广泛,传统上是使用氧化铟锡(Indium Tin Oxide,ITO)薄膜为透明导电薄膜,但其在高温应用上较不稳定并且易放出毒性,因此,铝掺杂氧化锌薄膜(ZnO∶Al,AZO)有逐渐取代ITO的趋势。本论文将探讨掺杂不同铝含量的影响,并且就其光电特性加以说明,最后得到其光的透过率~85%、电阻率~7.3×10-3Ω·cm以及面粗糙度~28nm的铝掺杂氧化锌薄膜,其具有表面粗化、电流分布层及窗口层的作用。并且将掺铝的氧化锌薄膜应用于氮化镓发光二极管上,以掺铝氧化锌微结构作为透明传导层的氮化镓发光二极管(λD=530nm,300×300μm)在20mA的工作电流下,其正向电压值为3.3V,输出功率达1.7mW,并且由光学显微镜图可以得知,小电流注下其电流分布均匀。若将AZO制作参数再作适当优化调整,取代ITO作为p型氮化镓上的透明传导层的可行性应该很高。

Growth of Al-doped ZnO Window Layer for GaN LED Application

Effects of Al doping on the morphology and structure of Al-doped ZnO(AZO) were discussed. Analysis of AZO was carried out by scanning electron microscopy, photoluminescence and double-crystal X-ray diffraction. The diffraction peak position of the (002) plane was shifted to a lower angle with increasing Al concentration. It was found that the UV emission peak of near band edge emission in PL has a blue-shift to a region of higher photon energy with increasing Al concentration. The AZO epilayer was used as surface texturing, uniform current spreading, high transparent and thick window layer for achieving a highly efficient LED. AZO was deposited on the GaN-based LEDs as the transparent conducting layer. Light transmission above ～85% in the wavelength ranging from 400 to 700 nm, and AZO resistivity and roughness of ～7.3×10-3 Ω·cm and ～28 nm were obtained, respectively. The OM image shows that the LED with an AZO layer can reach a uniform current spreading at a relatively low current intensity (～0.02 mA).