High-performance near-infrared photodetectors based on gate-controlled graphene–germanium Schottky junction with split active junction
Kim Cihyun,
Yoo Tae Jin,
Kwon Min Gyu,
Chang Kyoung Eun,
Hwang Hyeon Jun,
Lee Byoung Hun
Affiliations
Kim Cihyun
Department of Electrical Engineering, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do, 37673, Republic of Korea
Yoo Tae Jin
Department of Electrical Engineering, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do, 37673, Republic of Korea
Kwon Min Gyu
School of Materials Science and Engineering, Gwangju Institute of Science and Technology, 123, Cheomdangwagi-ro, Buk-gu, Gwangju, 61005, Republic of Korea
Chang Kyoung Eun
School of Materials Science and Engineering, Gwangju Institute of Science and Technology, 123, Cheomdangwagi-ro, Buk-gu, Gwangju, 61005, Republic of Korea
Hwang Hyeon Jun
Department of Electrical Engineering, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do, 37673, Republic of Korea
Lee Byoung Hun
Department of Electrical Engineering, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do, 37673, Republic of Korea
The structure of a gate-controlled graphene/germanium hybrid photodetector was optimized by splitting the active region to achieve highly sensitive infrared detection capability. The strengthened internal electric field in the split active junctions enabled efficient collection of photocarriers, resulting in a responsivity of 2.02 A W−1 and a specific detectivity of 5.28 × 1010 Jones with reduced dark current and improved external quantum efficiency; these results are more than doubled compared with the responsivity of 0.85 A W−1 and detectivity of 1.69 × 1010 Jones for a single active junction device. The responsivity of the optimized structure is 1.7, 2.7, and 39 times higher than that of previously reported graphene/Ge with Al2O3 interfacial layer, gate-controlled graphene/Ge, and simple graphene/Ge heterostructure photodetectors, respectively.
