Open AccessFloating-base germanium-tin heterojunction phototransistor for high-efficiency photodetection in short-wave infrared range
Author(s) -
Wei Wang,
Yuan Dong,
Shuh-Ying Lee,
Wan-Khai Loke,
Dian Lei,
S. F. Yoon,
Gengchiau Liang,
Xiao Gong,
Yee-Chia Yeo
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.018502
Subject(s) - responsivity , materials science , photodiode , germanium , optoelectronics , molecular beam epitaxy , heterojunction , photodetection , optics , dark current , infrared , photodetector , mercury cadmium telluride , biasing , epitaxy , silicon , voltage , physics , nanotechnology , layer (electronics) , quantum mechanics
The floating-base germanium-tin (Ge 1- xSnx) heterojunction phototransistor (HPT) is designed and investigated as an efficient optical receiver in the short-wave infrared range. Simulations indicate that as the Sn content increases, the responsivity significantly increases due to a higher absorption coefficient and a larger valence band offset between Ge and Ge 1- xSnx. Ge 0.935 Sn 0.065 HPTs that incorporated high-quality Ge 0.935 Sn 0.065 film grown by molecular beam epitaxy were fabricated, demonstrating optical response beyond wavelength of 2003 nm. At a low bias voltage of 1.0 V, optical response enhancement of ~10 times was achieved over the conventional Ge 0.935 Sn 0.065 p-i-n photodiode. High responsivities of ~1.8 A/W at 1550 nm and ~0.043 A/W at 2003 nm were demonstrated with low dark current density of 0.147 A/cm 2 .