Improving Light Output Power and Photovoltaic Performance of Thin-film Flip-chip InGaN-based Light-emitting Diodes Through KrF Laser Etching and Chemical Etching

• Main Authors: Tsung-HsienYu, 游宗憲
• Other Authors: Shui-Jinn Wang
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/tfnqc4

碩士 === 國立成功大學 === 微電子工程研究所 === 103 === In this study, an efficient, fast and simple surface texturing process using KrF laser irradiation in conjunction with hot KOH chemical wet etching on the undoped GaN (u-GaN) surface of TFFC-LEDs with a CuW-bonded substrate is demonstrated. The surface roughening scheme that comprises of dome and curved ramp of circular protrusions superimposed by hexagonal cones could be defined a three-fold roughening surface. The proposed surface roughening scheme could effectively improve total internal reflection (TIR) at the u-GaN/air interface. The effects of surface morphology after roughening processes with various numbers of KrF laser irradiation pulses on the performance of TFFC-LEDs are examined by ray-tracing simulations and experiments. As compared to regular-TFFC-LEDs without any etching process, the proposed TFFC-LEDs with 150-pulses of KrF laser irradiation and chemical wet etching (referred to as Device C-150) shows a typical increase in light output power (∆LOP/LOP) of LED by 13.08% at 350 mA. And the proposed Device C-150 shows a typical increase in maximum output power (∆Pmax/ Pmax) of solar cell by 12.87% under 1-sun air mass 1.5 global (AM1.5G) solar illumination. Under 100-sun AM 1.5G, Device C-150 exhibited best energy conversion efficiency of solar cell (η) with 2.06%. The enhancement of Device C-150 in η (∆η/η) was increased with 41.77% under 100-sun AM 1.5G, as compared to the same device under 1-sun AM 1.5G.