摘要
InAs/InAsSbⅡ类超晶格避免了InAs/GaSbⅡ类超晶格中与Ga原子相关的缺陷复合中心,具有更高的少数载流子寿命,在高工作温度中波红外探测器制备方面有着良好的应用前景。少数载流子单极势垒结构通常被用来抑制探测器暗电流,如nBn结构探测器。在InAs/InAsSbⅡ类超晶格nBn中波红外光电探测器中,势垒层常采用AlAsSb等多元合金材料,阻挡多数载流子的输运。然而,势垒层与吸收层存在的价带偏移(VBO)使得光电流往往需要在大偏压下饱和,从而增大了探测器暗电流。本文设计了一种AlAsSb/InAsSb超晶格势垒,旨在消除VBO并降低量子效率对偏压的依赖性。研究结果显示,150 K下,设计制备的nBn光电探测器的50%截止波长为4.5μm,探测器光响应在-50 mV的小反向偏压下达到了饱和,3.82μm处的峰值响应度为1.82 A/W,对应量子效率为58.8%。在150 K和-50 mV偏压下,探测器的暗电流密度为2.01×10^(-5)A/cm^(2),计算得到在3.82μm的峰值探测率为6.47×10^(11)cm·Hz^(1/2)/W。
InAs/InAsSb type-Ⅱsuperlattice(T2SL)materials hold great promise for the development of mid-wavelength infrared photodetectors operating at high temperatures,as they avoid the defects caused by Ga atoms in InAs/GaSb T2SL and exhibit long minority carrier lifetime.To reduce the dark current,minority carrier unipolar barrier structures,such as nBn detectors,are commonly employed.In mid-wavelength infrared InAs/InAsSb T2SL nBn photodetectors,the multielement alloy such as AlAsSb is typically utilized as the barrier layer to block the transport of majority carriers.However,the small valence band offset(VBO)between the barrier and absorption layers leads to the saturation of photocurrent at high bias voltage,resulting in increased dark current.In this work,an AlAsSb/InAsSb T2SL barrier was designed to eliminate the VBO and reduce the bias dependency of quantum efficiency.The results show that the fabricated nBn photodetector exhibits a 50%cutoff wavelength of 4.5μm at 150 K.The optical response of the photodetector saturates under a small bias of-50 mV,achieving a peak responsivity of 1.82 A/W at 3.82μm and a quantum efficiency of 58.8%.At 150 K and-50 mV applied bias,the photodetector exhibits a dark current density of 2.01×10^(-5)A/cm^(2)and a specific detectivity of 6.47×10^(11)cm·Hz^(1/2)/W.
作者
单一凡
吴东海
谢若愚
周文广
常发冉
李农
王国伟
蒋洞微
郝宏玥
徐应强
牛智川
SHAN Yi-Fan;WU Dong-Hai;XIE Ruo-Yu;ZHOU Wen-Guang;CHANG Fa-Ran;LINong;WANG Guo-Wei;JIANG Dong-Wei;HAO Hong-Yue;XU Ying-Qiang;NIU Zhi-huan(Key Laboratory of Optoelectronic Materials and Devices,Institute of Semiconductors,Chinese Academy of Sciences,Beijing 100083,China;College of Materials Science and Opto-Electronic Technology,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《红外与毫米波学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第4期450-456,共7页
Journal of Infrared and Millimeter Waves
基金
Supported by the Research Foundation for Advanced Talents of the Chinese Academy of Sciences(E27RBB03)。
