Performance enhancement of graphene/Ge near-infrared photodetector by modulating the doping level of graphene
Min Gyu Kwon,
Cihyun Kim,
Kyoung Eun Chang,
Tae Jin Yoo,
So-Young Kim,
Hyeon Jun Hwang,
Sanghan Lee,
Byoung Hun Lee
Affiliations
Min Gyu Kwon
Center for Emerging Electronic Devices and Systems, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, South Korea
Cihyun Kim
Department of Electrical Engineering, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do 37673, Republic of Korea
Kyoung Eun Chang
Center for Emerging Electronic Devices and Systems, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, South Korea
Tae Jin Yoo
Department of Electrical Engineering, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do 37673, Republic of Korea
So-Young Kim
Department of Electrical Engineering, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do 37673, Republic of Korea
Hyeon Jun Hwang
Department of Electrical Engineering, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do 37673, Republic of Korea
Sanghan Lee
Center for Emerging Electronic Devices and Systems, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju 61005, South Korea
Byoung Hun Lee
Department of Electrical Engineering, Pohang University of Science and Technology, 77, Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do 37673, Republic of Korea
In this paper, we improved the performance of a near-infrared graphene/germanium heterojunction photodetector at atmospheric pressure and at room temperature. We applied graphene with p-type chemical doping (doping chemical: polyacrylic acid) to lower the graphene Fermi level and increase the Schottky barrier formed at the junction with Ge. The responsivity at 1550 nm is improved from 0.87 to 1.27 A/W after the doping process. At the same time, the dark current is reduced by 20 times and the detectivity of the optimized device is improved to 9.6 × 109 Jones, which is 540% improvement compared to the undoped graphene device. With the result of improving performance through this simple process, it will be able to contribute to the fabrication of highly reactive graphene/semiconductor based photodetectors and the development of near-infrared sensors.
