摘要
文章研究了InAlN/GaN和引入AlN界面插入层形成的InAlN/AlN/GaN材料的输运性质.样品均在蓝宝石上以脉冲金属有机物化学气相淀积法生长,霍尔迁移率变温特性具有典型的二维电子气(2DEG)特征.综合各种散射机理包括声学形变势散射、压电散射、极性光学声子散射、位错散射、合金无序散射和界面粗糙度散射,理论分析了温度对迁移率的影响,发现室温下两种材料中2DEG支配性的散射机理都是极性光学波散射和界面粗糙度散射;AlN插入层对InAlN/GaN材料迁移率的改善作用一方面是免除2DEG的合金无序散射,另外还显著改善异质界面,抑制了界面粗糙度散射.考虑到2DEG密度也是影响其迁移率的重要因素,结合实验数据给出了晶格匹配InAlN/GaN和InAlN/AlN/GaN材料的2DEG迁移率随电子密度变化的理论上限.
The lattice-matched InAlN/GaN structure is one kind of emerging material with high conductivity and used in GaN-based high electron mobility transistors （HEMTs）.The transport properties of lattice-matched InAlN/GaN structure and InAlN/AlN/GaN structure are studied.The samples are grown using pulsed metal organic chemical vapor deposition on sapphire substates.Both structures show temperature-dependent Hall mobilities with a typical behavior of two-dimensional electron gas （2DEG）.Theoretical analysis of the temperature dependence of mobility is carried out based on the comprehensive consideration of various scattering mechanisms such as acoustic deformation-potential,piezoelectric,polar optic phonon,dislocation,alloy disorder and interface roughness scattering.It is found that the dominant scattering mechanisms are the interface roughness scattering and the polar optic phonon scattering for both structures at room temperature.The insertion of AlN spacer layer into InAlN/GaN interface exempts 2DEG from alloy disorder scattering,more importantly results in a better interface,and restrains greatly interface roughness scattering.The influence of sheet density on 2DEG mobility is also considered,and the upper limit of density-dependent 2DEG mobility is given for lattice-matched InAlN/GaN and InAlN/AlN/GaN structures and compared with many reported experimental data.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2011年第11期597-602,共6页
Acta Physica Sinica
基金
国家科技重大专项(批准号:2008ZX01002-002)
国家自然科学基金(批准号:60890191)、国家自然科学基金重点项目(批准号:60736033)
高等学校博士学科点新教师基金项目(批准号:200807011012)资助的课题~~
