Mechanism of stress-driven composition evolution during hetero-epitaxy in a ternary AlGaN system.
Two AlGaN samples with different strain were designed to investigate mechanism of stress-driven composition evolution. It is discovered that AlGaN grown on AlN or (AlN/GaN superlattices (SLs))/GaN both consist of two distinct regions with different compositions: transition region and uniform region, which is attributed to the compositional pulling effect. The formation of the transition region is due to the partial stress release caused by the generation of misfit dislocations near the hetero-interface. And the Al composition in the uniform region depends on the magnitude of residual strain. The difference in relaxation degree is 80.5% for the AlGaN epilayers grown on different underlayers, leading to a large Al composition difference of 22%. The evolutionary process of Al composition along [0001] direction was investigated in detail.
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Chenguang
C
He
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Zhixin
Z
Qin
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Fujun
F
Xu
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Lisheng
L
Zhang
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Jiaming
J
Wang
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Mengjun
M
Hou
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Shan
S
Zhang
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.|Collaboration Innovation Center of Quantum Matter, Beijing 100084, China.
Xinqiang
X
Wang
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
Weikun
W
Ge
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.|Collaboration Innovation Center of Quantum Matter, Beijing 100084, China.
Bo
B
Shen