Effects of AlN interlayer on the transport properties of nearly lattice-matched InAlN/GaN heterostructures grown on sapphire by pulsed metal organic chemical vapor deposition

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• 作者：JunShuai Xue ; ^{junshuaixue@hotmail.com} ; JinCheng Zhang ; Wei Zhang ; Liang Li ; FanNa Meng ; Ming Lu ; Jing Ning ; Yue Hao
• 关键词：A1. Surface structure ; A3. Metal organic chemical vapor deposition ; B1. Nitrides ; B2. Semiconducting III&ndash ; V materials ; B2. Semiconducting indium compounds
• 刊名：Journal of Crystal Growth
• 出版年：2012
• 期刊代码：49_00220248
• 类别：ch
• 出版时间：15 March, 2012
• 卷：343
• 期：1
• 页码：110-114
• 文件大小：839 K

摘要

The effects of AlN interlayer thickness on the transport properties of nearly lattice-matched InAlN/GaN heterostructures grown on sapphire substrates by pulsed metal organic chemical vapor deposition have been studied in detail. A very high electron mobility of approximately 1425 cm²/V s at room temperature and 5308 cm²/V s at 77 K together with a two dimensional electron gas (2DEG) density of 1.75脳10¹³ cm^鈭? were obtained for nearly lattice-matched InAlN/GaN heterostructures with an optimum 鈭?.2 nm thick AlN interlayer. For comparison, InAlN/GaN heterostructure without AlN interlayer exhibited a 2DEG density of 1.61脳10¹³ cm^鈭? with low electron mobility of 949 and 2032 cm²/V s at room temperature and 77 K, respectively. This significant enhancement of electron mobility is mainly attributed to an optimized AlN interlayer, which provides a smooth interface between InAlN barrier layer and GaN buffer layer and hence remarkably reduces the alloy disorder scattering by suppressing carrier penetration from the GaN channel into the InAlN barrier layer. Simultaneously, a best surface morphology with a root mean square roughness value of 0.24 nm is obtained with the optimized AlN interlayer.