Epitaxial growth of strain-relaxed GeSn alloys on Si utilizing Sn-composition-graded buffer layer for mid-infrared photodetectors
Abstract
Germanium-tin (GeSn) alloys have strong potential for Si-based mid-infrared (MIR) photonics, owing to their composition-dependent tunable bandgap. Although two-dimensional materials such as PtTe₂, MoTe₂, and Bi₂O₂Se exhibit excellent MIR optical properties, GeSn offers the unique advantages of CMOS compatibility, wafer-scale epitaxial growth, and direct monolithic integration with silicon photonic platforms. However, the huge lattice mismatch between GeSn and Si, induces compressive strain and generates crystalline defects that deteriorate device performance. To address these challenges, we develop a Sn-composition-graded epitaxial growth approach to obtain high-Sn-content (~9.1 %), strain-relaxed GeSn films on Si via molecular beam epitaxy (MBE). The grown graded GeSn films exhibit a strain relaxation degree of 31.4%. Subsequently, we demonstrated a GeSn metal semiconductor metal (MSM) photodetector (PD), exhibiting the peak responsivity of value 0.55 A/W at λ=1200 nm and 0.022 A/W at cutoff wavelength of λ=2400 nm under an applied bias of 10 V, confirming the material's suitability for broadband MIR detection.
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BibTeX
@article{lee2026epitaxial,
title = {{Epitaxial growth of strain-relaxed GeSn alloys on Si utilizing Sn-composition-graded buffer layer for mid-infrared photodetectors}},
author = {Kuo-Chih Lee and Ping-Chien Hsieh and Yue-Tong Jheng and Radhika Bansal and Yu Cheng and Yoshishige Tsuchiya and Jun-Yu Ou and Xin Zhou and Pavels Onufrijevs and Alexander Fedorchenko and H H Cheng and Guo-En Chang},
journal = {Optical Materials},
year = {2026},
month = sep,
doi = {10.1016/j.optmat.2026.118509},
url = {https://hal.science/hal-05765483v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Epitaxial growth of strain-relaxed GeSn alloys on Si utilizing Sn-composition-graded buffer layer for mid-infrared photodetectors
AU - Kuo-Chih Lee
AU - Ping-Chien Hsieh
AU - Yue-Tong Jheng
AU - Radhika Bansal
AU - Yu Cheng
AU - Yoshishige Tsuchiya
AU - Jun-Yu Ou
AU - Xin Zhou
AU - Pavels Onufrijevs
AU - Alexander Fedorchenko
AU - H H Cheng
AU - Guo-En Chang
PY - 2026
DA - 2026/09/19
JO - Optical Materials
DO - 10.1016/j.optmat.2026.118509
UR - https://hal.science/hal-05765483v1
AB - Germanium-tin (GeSn) alloys have strong potential for Si-based mid-infrared (MIR) photonics, owing to their composition-dependent tunable bandgap. Although two-dimensional materials such as PtTe₂, MoTe₂, and Bi₂O₂Se exhibit excellent MIR optical properties, GeSn offers the unique advantages of CMOS compatibility, wafer-scale epitaxial growth, and direct monolithic integration with silicon photonic platforms. However, the huge lattice mismatch between GeSn and Si, induces compressive strain and generates crystalline defects that deteriorate device performance. To address these challenges, we develop a Sn-composition-graded epitaxial growth approach to obtain high-Sn-content (~9.1 %), strain-relaxed GeSn films on Si via molecular beam epitaxy (MBE). The grown graded GeSn films exhibit a strain relaxation degree of 31.4%. Subsequently, we demonstrated a GeSn metal semiconductor metal (MSM) photodetector (PD), exhibiting the peak responsivity of value 0.55 A/W at λ=1200 nm and 0.022 A/W at cutoff wavelength of λ=2400 nm under an applied bias of 10 V, confirming the material's suitability for broadband MIR detection.
SN - 0925-3467
SN - 1873-1252
ER -