1、第 42 卷第 4 期2023 年 8 月红 外 与 毫 米 波 学 报J.Infrared Millim.WavesVol.42，No.4August，2023文章编号：1001-9014（2023）04-0468-08DOI：10.11972/j.issn.1001-9014.2023.04.007Wavelength extended InGaAsBi near infrared photodetectorFENG Duo，DAI Jin-Meng，CAO You-Xiang，ZHANG Li-Yao*（Department of Physics，University of Shangh
2、ai for Science and Technology，Shanghai 200093，China）Abstract：InGaAs photodetector is widely used in SWIR detection.Bi incorporation into InGaAs can reduce the bandgap，extending the detection wavelength.By controlling of the In and Bi compositions，the detection wavelength could be extended to over 3
3、m from InyGa1-yAs1-xBix，lattice-matched to InP.An In0.394Ga0.606As0.913Bi0.087 p-i-n photodetector is designed and its performance is numerically investigated.Dark currents and responsivity spectra are calculated with different temperatures，absorption layer thicknesses and doping concentrations.A 50
4、%cutoff wavelength of 3 m is achieved.The proposed structure provides a feasible way to fabricate InGaAsBi based SWIR detector with longer detection wavelength.Key words：InGaAsBi，dark current，responsivity，SWIR波长拓展型InGaAsBi近红外探测器冯铎，代金梦，曹有祥，张立瑶*（上海理工大学 物理系，上海 200093）摘要：InGaAs光电探测器广泛应用于短波红外检测。在InGaAs中掺
5、入Bi可以减小带隙，延长探测波长。通过控制In和Bi的组分可使InyGa1-yAs1-xBix与InP晶格匹配，同时，扩展探测波长至3 m以上。设计并研究了In0.394Ga0.606As0.913Bi0.087 p-i-n光电探测器的光电性能。计算了不同温度、吸收层厚度和p（n）区掺杂浓度下的暗电流和响应率特性。获得了3 m的截止波长。该结构为拓展InP基晶格匹配的短波红外探测器的探测波长提供了一种可行的方法。关键词：铟镓砷铋；暗电流；响应率；短波红外中图分类号：TN215 文献标识码：AIntroductionShort-wave infrared（SWIR）detectors have
6、been widely used in night vision，optical fiber communications and environmental monitoring，etc1.Because of the high optical absorption coefficient and carrier mobility，InGaAs shows good performance in SWIR detection at room temperature.The cutoff wavelength of In0.53Ga0.47As detectors，lattice-matche
7、d to InP is 1.7 m.The In composition is further increased in InGaAs to extend detection wavelengths，however，high In content introduces lattice mismatch，thus deteriorates the device performances2，3.Many efforts have been made to compensate the lattice mismatch，such as introducing InxAl1-xAs graded bu
8、ffer layers between InGaAs and InP substrate4-7 and using In0.66Ga0.34As/InAs superlattices8.Whereas，the device performance is still nonideal，comparing to the performance of the device fabricated with strain-free InGaAs.Dilute bismides，which are formed by incorporating a small quantity of Bi atoms i
9、nto the traditional group III-V compound semiconductors，have attracted wide attentions9-10.The isoelectronic energy level of Bi lies in the valence bands（VB）of most III-Vs11，which results in the VB anti-crossing in dilute bismides，thus reducing the bandgap of dilute bismides.Moreover，Bi incorporatio
10、n could increase the spin-orbit splitting energy and suppress Auger recombination12.The bandgap reduction of InGaAsBi is about 56 meV/Bi%13，which is from the VB upshift14.In incorporation into InGaAs offers a bandgap reduction of 10 meV/In%12.InGaAsBi can be lattice matched to InP by controlling the
11、 In and Bi conReceived date：2023 02 02，revised date：2023 04 12 收稿日期：2023 02 02，修回日期：2023 04 12Foundation items：Supported by the National Natural Science Foundation of China（61904106）Biography：FENG Duo（1997-），male，Yangquan，master.Research area involves III-V Photoelectronic materials and devices.E-ma
12、il：.*Corresponding author：E-mail：4 期 FENG Duo et al：Wavelength extended InGaAsBi near infrared photodetectortents.Also，the detection wavelength of InGaAsBi could reach and exceed 3 m with proper In and Bi contents.Till now，the highest Bi content in InGaAsBi is 7.5%15.Strong photoluminescence spectra
13、 were achieved from both InGaAsBi thin films16 and QWs17.An In0.76GaAsBi0.027 photodetector on InP with a 50%cutoff wavelength of 2.63 m at RT was demonstrated in 201818.In0.47GaAsBi0.07/InAlAs single quantum well with an emission wavelength of 2.5 m was realized in 202019.Good electrical and optica
14、l properties make InGaAsBi a potential material for fabricating optoelectronic devices.In this work，we proposed an InyGa1-yAs1-xBix photodetector which is lattice matched to InP substrate by adjusting x and y.Dark currents and responsivities of the InGaAsBi detector were investigated theoretically.W
15、ith the proposed structure，a cutoff wavelength at 3 m was achieved.1 Method According to Vegard s law，the lattice constant of the quaternary alloy InyGa1-yAs1-xBix isaInGaAsBi=(1-x)(1-y)aInAs+x(1-y)aInBi+(1-x)yaGaAs+xyaGaBi,（1）InyGa1-yAs1-xBix is lattice matched to InP when y=0.53-1.56x12.Because th
16、e bandgap reductions of InyGa1-yAs1-xBix are 56 meV/Bi%and 10 meV/In%，the bandgap of InyGa1-yAs1-xBix lattice-matched to InP isEg=1.0465x2-3.9867x+0.7511.（2）When the Bi content is over 8.7%，the bandgap of InyGa1-yAs1-xBix is below 0.41 eV，thus the theoretical cutoff wavelength exceeds 3 m.In0.394Ga0.606As0.913Bi0.087 is proposed to fabricate SWIR detector，with detection wavelength extended to 3 m.Figure 1 shows the schematic structure of the proposed In0.394Ga0.606As0.913Bi0.087 p-i-n detector.T