[21a-211B-1~9] 4.2 Photonics Devices, Photonic Integrated Circuit and Silicon Phonics

▲ [21a-211B-4] GeSn Heterojunction Phototransistors on Silicon for High-Responsivity Short-Wave Infrared Photodetection

〇(M2C)Wei-Ting Hung¹, Guo-En Chang¹ (1.Nat. Chung Cheng Univ.)

Keywords:phototransistor, short-wave infrared, responsivity

Si-based photodetectors (PDs) capable of operating in the short-wave infrared (SWIR) have attracted increasing research attention for a wide range of applications including fiber-optical communication, Lidar, and imaging. Recently, GeSn alloys have been extensively investigated for efficient Si-based SWIR PDs because of its narrow bandgap and compatibility with standard complementary metal-oxide-semiconductor (CMOS) technology. Although GeSn-based PDs have been demonstrated with photodetection range covering the entire SWIR range, the responsivity is still not satisfactory, thereby limiting the performance. In this paper, we experimentally demonstrate a high-responsivity SWIR GeSn heterojunction phototransistor (HPT) on silicon. The photodetection range is extended to 1980 nm by using GeSn alloys as the active layer, and the maximum observed responsivity is 15.3 A/W at 1681 nm because of the current gain provided by the HPT structures. These results represent an important step for high-performance GeSn HPT for high-responsivity SWIR photodetection.