Degradation mechanism of two-dimensional electron gas density in high Al-content A1GaN/GaN heterostructures

• 来源期刊: 中国物理B（英文版）
• 关键词: degradation mechanism two-dimensional electron gas AlGaN/GaN heterostructures surface oxidation
• 年，卷（期）: 2009,（7）
• 页码范围: 2998-3001
• 页数: 4页
• 语种: 英文

摘要

This paper finds that the two-dimensional electron gas density in high Al-content AlGaN/GaN heterostructures exhibits an obvious time-dependent degradation after the epitaxial growth. The degradation mechanism was investigated in depth using Hall effect measurements, high resolution x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy. The results reveal that the formation of surface oxide is the main reason for the degradation, and the surface oxidation always occurs within the surface hexagonal defects for high Al-content AlGaN/GaN heterostructures.