High-quality Ge1−xSnx (x = 0–0.11) realized by UHV-CVD using Ge2H6 and SnCl4: Materials growth, structural/optical properties, and prototype IR photodetectors
Changjiang Xie,
Yue Li,
Zhengjie Wu,
Songsong Wu,
Yixin Wang,
Guangyang Lin,
Cheng Li,
Hui Cong,
Chi Xu,
Chunlai Xue
Affiliations
Changjiang Xie
Key Laboratory of Optoelectronic Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, People’s Republic of China
Yue Li
Key Laboratory of Optoelectronic Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, People’s Republic of China
Zhengjie Wu
Key Laboratory of Optoelectronic Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, People’s Republic of China
Songsong Wu
Department of Physics, OSED, Semiconductor Photonics Research Center, Xiamen University, Xiamen 361005, Fujian, People’s Republic of China
Yixin Wang
Key Laboratory of Optoelectronic Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, People’s Republic of China
Guangyang Lin
Department of Physics, OSED, Semiconductor Photonics Research Center, Xiamen University, Xiamen 361005, Fujian, People’s Republic of China
Cheng Li
Department of Physics, OSED, Semiconductor Photonics Research Center, Xiamen University, Xiamen 361005, Fujian, People’s Republic of China
Hui Cong
Key Laboratory of Optoelectronic Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, People’s Republic of China
Chi Xu
Key Laboratory of Optoelectronic Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, People’s Republic of China
Chunlai Xue
Key Laboratory of Optoelectronic Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, People’s Republic of China
GeSn materials with Sn contents ranging between 0% and 11% have been successfully grown by using Ge2H6 and SnCl4 in a hot-wall UHV-CVD system at low reaction pressures of 0.2–0.4 Torr. Both fully strained and partially relaxed materials have been produced. It was found that the materials were of high crystallinity as evidenced by few threading dislocations from cross-sectional TEM. Photoluminescence studies have shown that the PL spectra shift to longer wavelengths, and the PL intensity increases exponentially as the Sn contents increase. The photoemission cutoff for a 9.5% Sn sample is beyond 2600 nm, and low temperature PL measurements have confirmed that this sample is already in the direct gap material regime. Prototype photoconductor devices were fabricated with a partially strained 5% Sn sample, showing much smaller dark currents and similar spectral coverage as compared to a fully strained 7.8% Sn device reported in the literature. The reported technical route has provided a new path toward high quality, low cost GeSn epitaxy, and will contribute to the development of group IV optoelectronics.
