Xiong Fangzhu, Guo Weiling, Feng Shiwei, Li Xuan, Du Zaifa, Wang Le, Deng Jun, Sun Jie
Key Laboratory of Optoelectronics Technology, College of Microelectronics, Beijing University of Technology, Beijing 100124, China.
Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gothenburg, Sweden.
Materials (Basel). 2019 Oct 28;12(21):3533. doi: 10.3390/ma12213533.
In this work, we grew transfer-free graphene-like thin films (GLTFs) directly on gallium nitride (GaN)/sapphire light-emitting diode (LED) substrates. Their electrical, optical and thermal properties were studied for transparent electrode applications. Ultrathin platinum (2 nm) was used as the catalyst in the plasma-enhanced chemical vapor deposition (PECVD). The growth parameters were adjusted such that the high temperature exposure of GaN wafers was reduced to its minimum (deposition temperature as low as 600 °C) to ensure the intactness of GaN epilayers. In a comparison study of the Pt-GLTF GaN LED devices and Pt-only LED devices, the former was found to be superior in most aspects, including surface sheet resistance, power consumption, and temperature distribution, but not in optical transmission. This confirmed that the as-developed GLTF-based transparent electrodes had good current spreading, current injection and thermal spreading functionalities. Most importantly, the technique presented herein does not involve any material transfer, rendering a scalable, controllable, reproducible and semiconductor industry-compatible solution for transparent electrodes in GaN-based optoelectronic devices.
在这项工作中，我们直接在氮化镓（GaN）/蓝宝石发光二极管（LED）衬底上生长了无转移的类石墨烯薄膜（GLTFs）。研究了它们用于透明电极应用时的电学、光学和热学性质。在等离子体增强化学气相沉积（PECVD）中，使用超薄铂（2纳米）作为催化剂。调整生长参数，使GaN晶片的高温暴露降至最低（沉积温度低至600°C），以确保GaN外延层的完整性。在对基于Pt-GLTF的GaN LED器件和仅含Pt的LED器件的比较研究中，发现前者在大多数方面表现更优，包括表面薄层电阻、功耗和温度分布，但在光传输方面并非如此。这证实了所开发的基于GLTF的透明电极具有良好的电流扩展、电流注入和热扩散功能。最重要的是，本文提出的技术不涉及任何材料转移，为基于GaN的光电器件中的透明电极提供了一种可扩展、可控、可重复且与半导体工业兼容的解决方案。
