School of Electrical Engineering, Korea University , Seoul 136-701, Republic of Korea.
ACS Appl Mater Interfaces. 2017 Jul 19;9(28):24357-24364. doi: 10.1021/acsami.7b06362. Epub 2017 Jul 10.
A hybrid-type transparent conductive electrode (H-TCE) structure comprising an AlN rod array with conducting filaments (CFs) and indium tin oxide (ITO) films is proposed to improve both current injection and distribution as well as optical transmittance in the UV region. These CFs, generated in UV-transparent AlN rod areas using an electric field, can be used as conducting paths for carrier injection from a metal to a semiconductor such as p-(Al)GaN, which allows perfect Ohmic behavior with high transmittance (>95% at 365 nm) to be obtained. In addition, conduction across AlN rods and Ohmic conduction mechanisms are investigated by analyzing AlN rods and AlN rod/p-AlGaN film interfaces. We apply these H-TCEs to three near-UV light-emitting diodes (LEDs) (385 nm LEDs with p-GaN and p-AlGaN terminated surfaces and 365 nm LED with p-AlGaN terminated surface). We confirm that the light power outputs increase by 66%, 79%, and 103%, whereas the forward voltages reduce by 5.6%, 10.2%, and 8.6% for 385 nm p-GaN terminated, 385 nm p-AlGaN terminated, and 365 nm p-AlGaN terminated LEDs with H-TCEs, respectively, compared to LEDs with reference ITOs.
提出了一种包含氮化铝（AlN）棒阵列为透明导电电极（TCE）结构的混合透明导电电极（H-TCE）结构，其具有导电细丝（CFs）和氧化铟锡（ITO）薄膜，以改善电流注入和分布以及紫外区域的光透过率。这些 CFs 是在紫外透明的 AlN 棒区域中利用电场产生的，可以用作从金属到半导体（如 p-（Al）GaN）的载流子注入的导电路径，从而可以获得具有高透过率（在 365nm 时>95%）的完美欧姆行为。此外，通过分析 AlN 棒和 AlN 棒/p-AlGaN 薄膜界面，研究了 AlN 棒之间的导通和欧姆导通机制。我们将这些 H-TCE 应用于三种近紫外发光二极管（LED）（具有 p-GaN 和 p-AlGaN 终止表面的 385nm LED 以及具有 p-AlGaN 终止表面的 365nm LED）。我们确认，与具有参考 ITO 的 LED 相比，对于具有 H-TCE 的 385nm p-GaN 终止、385nm p-AlGaN 终止和 365nm p-AlGaN 终止 LED，光功率输出分别增加了 66%、79%和 103%，而正向电压分别降低了 5.6%、10.2%和 8.6%。
