以銦錫氧化物長在n++短週期超晶格上層接觸的高亮度氮化銦鎵綠光發光二極體

銦錫氧化物（ITO）（260nm）和鎳（5nm）／金（10nm）薄膜分別沉積在玻璃基板，p型氮化鎵，n+型氮化銦鎵/氮化鎵短週期超晶格，n++短週期超晶格和氮化鎵綠光發光二極體。發現銦錫氧化物可以提供相當高的光穿透率（i.e. 95% at 520nm）。我們也發現銦錫氧化物沉積在n++短週期超晶格的特徵接觸電阻是相當小的，約1.03×10-3Ωcm2。雖然發光二極體以銦錫氧化物成長在n++短週期超晶格形成上電極，比起以鎳／金長在n++短週期超晶格上層電極之發光二極體有著稍高的順向操作電壓；不過以銦錫氧化物長在n++短週期超晶格上層電極之綠光發光二極體，其20mA光輸出功率和外部量子效率，分別可達到4.98mW以及8.2%，得到的結果比起以鎳／金長在n++短週期超晶格上層電極之綠光發光二極體是高出很多。我們也發現以銦錫氧化物長在n++短週期超晶格上層電極之發光二極體，其可靠度也是相當不錯的。

Indium tin oxide (ITO)(260nm) and Ni(5nm)/Au(10nm) films were deposited onto glass substrates, p-GaN layers, n+-InGaN/GaN short-period-superlattice (SPS), n++-SPS and nitride-based green light emitting diodes (LEDs). It was found that ITO could provide us an extremely high transparency (i.e. 95% at 520 nm). It was also found that the 1.03×10-3 W-cm2 specific contact resistance of ITO on n++-SPS was reasonably small. Although forward voltage of the LED with ITO on n ++-SPS upper contact was slightly higher than that of the LED with Ni/Au on n++-SPS upper contact, 20 mA output power and external quantum efficiency of the green LED with ITO on n++-SPS upper contact could reach 4.98 mW and 8.2%, respectively, which were much larger than those observed from the green LED with Ni/Au on n++-SPS upper contact. The reliability of ITO on n++-SPS upper contact was also found to be reasonably good.