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新的氧化物结构清除了AlGaN/GaN异构结构中二维电子气体的起源
Zhixiu Wang1,2, Wencai Yi3, Yiqing Cao3
1Administrative Office of Laboratory and Equipment, Qufu Normal University, Qufu 273165, China.
The Journal of chemical physics
|November 15, 2023
概括
研究人员发现了新的稳定氧化物结构,对于控制AlGaN/GaN异构中的二维电子气体 (2DEG) 至关重要. 这些发现澄清了实验观测,并使先进的半导体设备能够精确控制2DEG.
科学领域:
- 材料科学 材料科学 材料科学
- 表面科学是一门学科.
- 半导体物理 半导体物理
背景情况:
- 在AlGaN/GaN异构中对二维电子气体 (2DEG) 的精确控制对于高性能半导体设备至关重要.
- 确切的氧化物表面结构,负责诱导2DEG仍然不清楚,现有的模型,如氧化物静电测量 (OS) 匹配和电子计数 (EC) 规则呈现能量限制.
研究的目的:
- 使用全局优化算法在GaN (0001) 和AlN (0001) 表面上探索和识别稳定的氧化物表面结构.
- 为了澄清围绕氧化物表面结构的模糊性,这些结构在AlGaN/GaN异构结构中诱导2DEG.
- 提出新的,能量有利的氧化物结构,可以解释实验观测,并促进2DEG控制.
主要方法:
- 利用全局优化算法系统地研究GaN和AlN表面的潜在氧化结构.
- 执行电子结构计算,以确定拟议的氧化物结构的特性.
- 分析了表面能量和占地面状态相对于散带间隙的位置.
主要成果:
- 成功复制了之前报告的氧化结构,验证了全球优化方法.
- 在每个氧化物层中发现了两个相似的,在能量上接近的氧化物结构,解释了在550°C以下无序层的实验观测.
- 建议在特定条件下 (富有酸,缺乏氧气) 具有明显低于EC规则结构的表面能量的新型,稳定的氧化物结构.
- 证明这些新的OS匹配结构具有中间距离以上的被占有状态,将其确定为2DEG的起源.
结论:
- 开发的全球优化方法有效地识别了GaN/AlN表面上稳定的氧化物结构.
- 已经确定了具有较低表面能量的新的氧化物静态度匹配结构,特别是在丰富和缺乏氧气的条件下.
- 这些新提出的OS结构被证实是AlGaN/GaN异构结构中的2DEG的来源,为增强的设备设计提供了一条途径.
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