Intrinsic carrier multiplication in layered Bi2O2Se avalanche photodiodes with gain bandwidth product exceeding 1 GHz

• 作者: Vinod K.Sangwan Joohoon Kang David Lam J.Tyler Gish Spencer A.Wells Jan Luxa James P.Male G.Jeffrey Snyder Zdenek Sofer Mark C.Hersam
• 来源期刊: 纳米研究（英文版）
• 年，卷（期）: 2021,（6）
• 所属期刊栏目: Synthesis
• 页码范围: 1961-1966
• 页数: 6页
• 语种: 英文

摘要

Emerging layered semiconductors present multiple advantages for optoelectronic technologies including high carrier mobilities,strong light-matter interactions,and tunable optical absorption and emission.Here,metal-semiconductor-metal avalanche photodiodes (APDs) are fabricated from Bi2O2Se crystals,which consist of electrostatically bound[Bi2O2]2+ and[Se]2-layers.The resulting APDs possess an intrinsic carrier multiplication factor up to 400 at 7 K with a responsivity gain exceeding 3,000 A/W and bandwidth of ～ 400 kHz at a visible wavelength of 515.6 nm,ultimately resulting in a gain bandwidth product exceeding 1 GHz.Due to exceptionally low dark currents,Bi2O2Se APDs also yield high detectivities up to 4.6 × 1014 Jones.A systematic analysis of the photocurrent temperature and bias dependence reveals that the carrier multiplication process in Bi2O2Se APDs is consistent with a reverse biased Schottky diode model with a barrier height of ～ 44 meV,in contrast to the charge trapping extrinsic gain mechanism that dominates most layered semiconductor phototransistors.In this manner,layered Bi2O2Se APDs provide a unique platform that can be exploited in a diverse range of high-performanca photodetector applications.