为提高势垒型中波InAs/InAsSb二类超晶格红外探测器器件性能,研究并设计了nBn势垒型InAs/InAsSb器件结构。针对InAs/InAsSb红外探测器器件结构特征,分析了暗电流的主导机制和能带特性,采用基于泊松方程、连续性方程和热方程的数值计算方...为提高势垒型中波InAs/InAsSb二类超晶格红外探测器器件性能,研究并设计了nBn势垒型InAs/InAsSb器件结构。针对InAs/InAsSb红外探测器器件结构特征,分析了暗电流的主导机制和能带特性,采用基于泊松方程、连续性方程和热方程的数值计算方法,通过精确调控吸收层掺杂、势垒层掺杂、势垒层厚度、温度和组分等,构建出高能量势垒以有效阻挡多数载流子,允许少数载流子迁移,实现价带偏移(Valence Band Offset,VBO)接近于零的要求,从而有效降低暗电流。研究结果表明,在1×10^(15)~1×10^(17)cm^(-3)范围内降低势垒层掺杂浓度,VBO和暗电流开启电压绝对值均会减小,当AlAs1-xSbx势垒中Sb组分为0.91时,VBO接近于零。对于吸收层,随着掺杂浓度的提高,暗电流呈现减小趋势,但趋势较不明显。在-0.5V偏压,140 K工作条件下,吸收层和势垒层掺杂浓度分别为1×10^(13)cm^(-3),1×10^(15)cm^(-3),吸收层与势垒层厚度分别为3μm,80 nm,得到器件结构参数优化后的暗电流低至4.5×10^(-7)A/cm^(2),证明InAs/InAsSb中波红外探测器具有高温工作的应用前景,可广泛应用于导弹预警、红外制导、航空航天等领域。展开更多
采用分子束外延技术在GaSb衬底上生长了PIN型长波红外28 ML InAs/7 ML InAs0.48Sb0.52超晶格探测器材料,研究了Sb浸润界面对其表面形貌、晶体结构和光电性能的影响。结果发现:相对于无界面控制的超晶格,采用Sb浸润界面的超晶格表面更平...采用分子束外延技术在GaSb衬底上生长了PIN型长波红外28 ML InAs/7 ML InAs0.48Sb0.52超晶格探测器材料,研究了Sb浸润界面对其表面形貌、晶体结构和光电性能的影响。结果发现:相对于无界面控制的超晶格,采用Sb浸润界面的超晶格表面更平整,表面粗糙度仅为1.28;超晶格晶体结构更完整,界面起伏明显减小,与衬底的晶格失配度由3.26%减小到2.97%。InAs/InAsSb超晶格探测器的50%截止波长为10μm,量子效率为3.1%;Sb浸润界面的超晶格具有更低的暗电流和更高的微分阻抗,-50 mV偏压下暗电流密度为0.12 A/cm^ 2,零偏阻抗面积乘积(R 0A)为0.44Ω·cm^2,计算得到探测率为5.06×10^7 cm·Hz 1/2/W。Sb浸润界面有效抑制了Sb的扩散,提高了超晶格的晶体质量和探测性能,但失配应力依然很大。这些结果为高质量长波红外InAs/InAsSb超晶格的界面生长提供了依据。展开更多
Ga-free InAs/InAsSb type-Ⅱ superlattices(T2SL) have extensive application prospective in infrared photodetectors. Achieving higher operation temperature is critical to its commercial applications. Here, a fractional ...Ga-free InAs/InAsSb type-Ⅱ superlattices(T2SL) have extensive application prospective in infrared photodetectors. Achieving higher operation temperature is critical to its commercial applications. Here, a fractional monolayer alloy method was used to grow InAsSb alloy with better controlled alloy composition. The as-grown T2SL gave eleven satellite peaks and a first satellite peak with a narrow full-width-half-maximum (FWHM) of 20.5arcsec (1 arcsec=0.01592°). Strain mapping results indicated limited Sb diffusion through the As-Sb exchange process at the interface. Moreover, unlike interface states caused by the As-Sb exchange effect, this relatively clear interface was distinctive with localized states with higher activation energies of the non-radiative recombination process ((18±1) meV and (84±12) meV at different temperature ranges), which means that this interface state introduced by fractional monolayer alloy growth method can effectively suppress Auger recombination process in T2SL. Through this interface engineering of InAs/InAsSb Type-Ⅱ superlattice, it achieved detective photoluminescence (PL) signal with the center wavelength of 9μm at 250K.展开更多
In this paper,we demonstrate nBn InAs/InAsSb type II superlattice(T2SL)photodetectors with AlAsSb as the barrier that targets mid-wavelength infrared(MWIR)detection.To improve operating temperature and suppress dark c...In this paper,we demonstrate nBn InAs/InAsSb type II superlattice(T2SL)photodetectors with AlAsSb as the barrier that targets mid-wavelength infrared(MWIR)detection.To improve operating temperature and suppress dark current,a specific Sb soaking technique was employed to improve the interface abruptness of the superlattice with device passivation using a SiO_(2) layer.These result in ultralow dark current density of 6.28×10^(-6)A/cm^(2)and 0.31 A/cm^(2)under-600 mV at 97 K and297 K,respectively,which is lower than most reported InAs/InAsSb-based MWIR photodetectors.Corresponding resistance area product values of 3.20×10^(4)Ω·cm^(2)and 1.32Ω·cm^(2)were obtained at 97 K and 297 K.A peak responsivity of 0.39 A/W with a cutoff wavelength around 5.5μm and a peak detectivity of 2.1×10^(9)cm·Hz^(1/2)/W were obtained at a high operating temperature up to 237 K.展开更多
Weak response in long‐wavelength infrared(LWIR)detection has long been a perennial concern,significantly limiting the reliability of appli-cations.Avalanche photodetectors(APDs)offer excellent responsivity but are pl...Weak response in long‐wavelength infrared(LWIR)detection has long been a perennial concern,significantly limiting the reliability of appli-cations.Avalanche photodetectors(APDs)offer excellent responsivity but are plagued by high dark current during the multiplication process.Here,we propose a high‐performance type‐II superlattices(T2SLs)LWIR APD to address these issues.The low Auger recombination rate of the InAs/InAsSb T2SLs absorption layer is exploited to reduce the dark current initially.AlAsSb with a low k value is employed as the multiplication layer to suppress device noise while maintaining sufficient gain.To facilitate carrier transport,the conduction band discontinuity is opti-mized by inserting an InAs/AlSb T2SLs stepped grading layer between the absorption and multiplication layers.As a result,the device exhibits excellent photoresponse at 8.4μm at 100 K and maintains a low dark current density of 5.4810^(-2) A/cm^(2).Specifically,it achieves a maximum gain of 366,a responsivity of 650 A/W,and a quantum efficiency of 26.28%under breakdown voltage.This design offers a promising solution for the advancement of LWIR detection.展开更多
The lattice-matched XBn structures of InAsSb,grown on GaSb substrates,exhibit high crystal quali⁃ty,and can achieve extremely low dark currents at high operating temperatures(HOT).Its superior performance is attribute...The lattice-matched XBn structures of InAsSb,grown on GaSb substrates,exhibit high crystal quali⁃ty,and can achieve extremely low dark currents at high operating temperatures(HOT).Its superior performance is attributed to the unipolar barrier,which blocks the majority carriers while allowing unhindered hole transport.To further explore the energy band and carrier transport mechanisms of the XBn unipolar barrier structure,this pa⁃per systematically investigates the influence of doping on the dark current,photocurrent,and tunneling character⁃istics of InAsSb photodetectors in the PBn structure.Three high-quality InAsSb samples with unintentionally doped absorption layers(AL)were prepared,with varying p-type doping concentrations in the GaSb contact layer(CL)and the AlAsSb barrier layer(BL).As the p-type doping concentration in the CL increased,the device’s turn-on bias voltage also increased,and p-type doping in the BL led to tunneling occurring at lower bias voltages.For the sample with UID BL,which exhibited an extremely low dark current of 5×10^(-6) A/cm^(2).The photocurrent characteristics were well-fitted using the back-to-back diode model,revealing the presence of two opposing space charge regions on either side of the BL.展开更多
In this paper,a planar junction mid-wavelength infrared(MWIR)photodetector based on an InAs/GaSb type-Ⅱsuper-lattices(T2SLs)is reported.The Intrinsic-πMN superlattices was grown by the molecular beam epitaxy(MBE),fo...In this paper,a planar junction mid-wavelength infrared(MWIR)photodetector based on an InAs/GaSb type-Ⅱsuper-lattices(T2SLs)is reported.The Intrinsic-πMN superlattices was grown by the molecular beam epitaxy(MBE),followed with a ZnS layer grown by the chemical vapor deposition(CVD).The p-type contact layer was constructed by thermal diffusion in the undoped superlattices.The Zinc atom was successfully realised into the superlattice and a PπMN T2SL structure was con-structed.Furthermore,the effects of different diffusion temperatures on the dark current performance of the devices were researched.The 50%cut-off wavelength of the photodetector is 5.26μm at 77 K with 0 V bias.The minimum dark current density is 8.67×10^(−5) A/cm^(2) and the maximum quantum efficiency of 42.5%,and the maximum detectivity reaches 3.90×10^(10) cm·Hz^(1/2)/W at 77 K.The 640×512 focal plane arrays(FPA)based on the planner junction were fabricated afterwards.The FPA achieves a noise equivalent temperature difference(NETD)of 539 mK.展开更多
本文报道了1280×1024元InAs/GaSb II类超晶格中/中波双色红外焦平面阵列探测器的研究结果。探测器采用PN-NP叠层双色外延结构,信号提取采用叠层双色结构和顺序读出方式。运用分子束外延技术在GaSb衬底上生长超晶格材料,双波段红外...本文报道了1280×1024元InAs/GaSb II类超晶格中/中波双色红外焦平面阵列探测器的研究结果。探测器采用PN-NP叠层双色外延结构,信号提取采用叠层双色结构和顺序读出方式。运用分子束外延技术在GaSb衬底上生长超晶格材料,双波段红外吸收区的超晶格周期结构分别为中波1:6 ML InAs/7 ML GaSb和中波2:9 ML InAs/7 ML GaSb。焦平面阵列像元中心距为12μm。在80 K时测试,器件双波段的工作谱段为中波1:3~4μm,中波2:3.8~5.2μm。中波1器件平均峰值探测率达到6.32×10^(11) cm·Hz^(1/2)W^(-1),中波2器件平均峰值探测率达到2.84×10^(11) cm·Hz^(1/2)W^(-1)。红外焦平面偏压调节成像测试得到清晰的双波段成像。本文是国内首次报道1280×1024规模InAs/GaSb II类超晶格中/中波双色红外焦平面探测器。展开更多
文摘为提高势垒型中波InAs/InAsSb二类超晶格红外探测器器件性能,研究并设计了nBn势垒型InAs/InAsSb器件结构。针对InAs/InAsSb红外探测器器件结构特征,分析了暗电流的主导机制和能带特性,采用基于泊松方程、连续性方程和热方程的数值计算方法,通过精确调控吸收层掺杂、势垒层掺杂、势垒层厚度、温度和组分等,构建出高能量势垒以有效阻挡多数载流子,允许少数载流子迁移,实现价带偏移(Valence Band Offset,VBO)接近于零的要求,从而有效降低暗电流。研究结果表明,在1×10^(15)~1×10^(17)cm^(-3)范围内降低势垒层掺杂浓度,VBO和暗电流开启电压绝对值均会减小,当AlAs1-xSbx势垒中Sb组分为0.91时,VBO接近于零。对于吸收层,随着掺杂浓度的提高,暗电流呈现减小趋势,但趋势较不明显。在-0.5V偏压,140 K工作条件下,吸收层和势垒层掺杂浓度分别为1×10^(13)cm^(-3),1×10^(15)cm^(-3),吸收层与势垒层厚度分别为3μm,80 nm,得到器件结构参数优化后的暗电流低至4.5×10^(-7)A/cm^(2),证明InAs/InAsSb中波红外探测器具有高温工作的应用前景,可广泛应用于导弹预警、红外制导、航空航天等领域。
基金Supported by the National Natural Science Foundation of China(61774130,11474248,61790581,51973070)the Ph.D.Pro⁃grams Foundation of Ministry of Education of China(20105303120002)National Key Technology Research and Development Program of the Ministry of Sci⁃ence and Technology of China(2018YFA0209101).
基金financially supported by the National Natural Science Foundation of China (Nos. 62074018 and 61704011)the China Postdoctoral Science Foundation Funded Project (Nos. 2019M652176 and 2019M661680)+4 种基金the Developing Project of Science and Technology of Jilin Province (Nos. 20200301052RQ, 20200201266JC, 20190701029GH, 20180519017JH and 20180520177JH)the Project of Education Department of Jilin Province (No. JJKH20210831KJ)the Natural Science Foundation of Guangdong Province (No. 2020A1515010868)Shenzhen Fundamental Research Fund (No. JCYJ20180307151538972)supported by R&D project of Collighter Co., Ltd。
文摘Ga-free InAs/InAsSb type-Ⅱ superlattices(T2SL) have extensive application prospective in infrared photodetectors. Achieving higher operation temperature is critical to its commercial applications. Here, a fractional monolayer alloy method was used to grow InAsSb alloy with better controlled alloy composition. The as-grown T2SL gave eleven satellite peaks and a first satellite peak with a narrow full-width-half-maximum (FWHM) of 20.5arcsec (1 arcsec=0.01592°). Strain mapping results indicated limited Sb diffusion through the As-Sb exchange process at the interface. Moreover, unlike interface states caused by the As-Sb exchange effect, this relatively clear interface was distinctive with localized states with higher activation energies of the non-radiative recombination process ((18±1) meV and (84±12) meV at different temperature ranges), which means that this interface state introduced by fractional monolayer alloy growth method can effectively suppress Auger recombination process in T2SL. Through this interface engineering of InAs/InAsSb Type-Ⅱ superlattice, it achieved detective photoluminescence (PL) signal with the center wavelength of 9μm at 250K.
基金supported by the National Science and Technology Major Project(No.2018YFE0200900)。
文摘In this paper,we demonstrate nBn InAs/InAsSb type II superlattice(T2SL)photodetectors with AlAsSb as the barrier that targets mid-wavelength infrared(MWIR)detection.To improve operating temperature and suppress dark current,a specific Sb soaking technique was employed to improve the interface abruptness of the superlattice with device passivation using a SiO_(2) layer.These result in ultralow dark current density of 6.28×10^(-6)A/cm^(2)and 0.31 A/cm^(2)under-600 mV at 97 K and297 K,respectively,which is lower than most reported InAs/InAsSb-based MWIR photodetectors.Corresponding resistance area product values of 3.20×10^(4)Ω·cm^(2)and 1.32Ω·cm^(2)were obtained at 97 K and 297 K.A peak responsivity of 0.39 A/W with a cutoff wavelength around 5.5μm and a peak detectivity of 2.1×10^(9)cm·Hz^(1/2)/W were obtained at a high operating temperature up to 237 K.
基金Fundamental Research Funds for the Central Universities,Grant/Award Number:ZYGX2019Z018National Natural Science Foundation of China,Grant/Award Number:61974014Innovation Group Project of Sichuan Province,Grant/Award Number:20CXTD0090。
文摘Weak response in long‐wavelength infrared(LWIR)detection has long been a perennial concern,significantly limiting the reliability of appli-cations.Avalanche photodetectors(APDs)offer excellent responsivity but are plagued by high dark current during the multiplication process.Here,we propose a high‐performance type‐II superlattices(T2SLs)LWIR APD to address these issues.The low Auger recombination rate of the InAs/InAsSb T2SLs absorption layer is exploited to reduce the dark current initially.AlAsSb with a low k value is employed as the multiplication layer to suppress device noise while maintaining sufficient gain.To facilitate carrier transport,the conduction band discontinuity is opti-mized by inserting an InAs/AlSb T2SLs stepped grading layer between the absorption and multiplication layers.As a result,the device exhibits excellent photoresponse at 8.4μm at 100 K and maintains a low dark current density of 5.4810^(-2) A/cm^(2).Specifically,it achieves a maximum gain of 366,a responsivity of 650 A/W,and a quantum efficiency of 26.28%under breakdown voltage.This design offers a promising solution for the advancement of LWIR detection.
基金Supported by the Candidate Talents Training Fund of Yunnan Province(202205AC160054)the National Natural Science Foundation of China(62174156)。
文摘The lattice-matched XBn structures of InAsSb,grown on GaSb substrates,exhibit high crystal quali⁃ty,and can achieve extremely low dark currents at high operating temperatures(HOT).Its superior performance is attributed to the unipolar barrier,which blocks the majority carriers while allowing unhindered hole transport.To further explore the energy band and carrier transport mechanisms of the XBn unipolar barrier structure,this pa⁃per systematically investigates the influence of doping on the dark current,photocurrent,and tunneling character⁃istics of InAsSb photodetectors in the PBn structure.Three high-quality InAsSb samples with unintentionally doped absorption layers(AL)were prepared,with varying p-type doping concentrations in the GaSb contact layer(CL)and the AlAsSb barrier layer(BL).As the p-type doping concentration in the CL increased,the device’s turn-on bias voltage also increased,and p-type doping in the BL led to tunneling occurring at lower bias voltages.For the sample with UID BL,which exhibited an extremely low dark current of 5×10^(-6) A/cm^(2).The photocurrent characteristics were well-fitted using the back-to-back diode model,revealing the presence of two opposing space charge regions on either side of the BL.
基金supported by the National Key Technologies R&D Program of China(Grant Nos.2024YFA1208904,2019YFA0705203)Major Program of the National Natural Science Foundation of China(Grant Nos.62004189,61274013)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0460000)the Research Foundation for Advanced Talents of the Chinese Academy of Sciences(Grant No.E27RBB03).
文摘In this paper,a planar junction mid-wavelength infrared(MWIR)photodetector based on an InAs/GaSb type-Ⅱsuper-lattices(T2SLs)is reported.The Intrinsic-πMN superlattices was grown by the molecular beam epitaxy(MBE),followed with a ZnS layer grown by the chemical vapor deposition(CVD).The p-type contact layer was constructed by thermal diffusion in the undoped superlattices.The Zinc atom was successfully realised into the superlattice and a PπMN T2SL structure was con-structed.Furthermore,the effects of different diffusion temperatures on the dark current performance of the devices were researched.The 50%cut-off wavelength of the photodetector is 5.26μm at 77 K with 0 V bias.The minimum dark current density is 8.67×10^(−5) A/cm^(2) and the maximum quantum efficiency of 42.5%,and the maximum detectivity reaches 3.90×10^(10) cm·Hz^(1/2)/W at 77 K.The 640×512 focal plane arrays(FPA)based on the planner junction were fabricated afterwards.The FPA achieves a noise equivalent temperature difference(NETD)of 539 mK.
文摘本文报道了1280×1024元InAs/GaSb II类超晶格中/中波双色红外焦平面阵列探测器的研究结果。探测器采用PN-NP叠层双色外延结构,信号提取采用叠层双色结构和顺序读出方式。运用分子束外延技术在GaSb衬底上生长超晶格材料,双波段红外吸收区的超晶格周期结构分别为中波1:6 ML InAs/7 ML GaSb和中波2:9 ML InAs/7 ML GaSb。焦平面阵列像元中心距为12μm。在80 K时测试,器件双波段的工作谱段为中波1:3~4μm,中波2:3.8~5.2μm。中波1器件平均峰值探测率达到6.32×10^(11) cm·Hz^(1/2)W^(-1),中波2器件平均峰值探测率达到2.84×10^(11) cm·Hz^(1/2)W^(-1)。红外焦平面偏压调节成像测试得到清晰的双波段成像。本文是国内首次报道1280×1024规模InAs/GaSb II类超晶格中/中波双色红外焦平面探测器。
