Type-Ⅱ InAs/GaSb superlattiees made of 13 InAs monolayers （MLs） and 7 GaSb MLs are grown on GaSb substrates by solid source molecular beam epitaxy. To obtain lattice-matched structures, thin InSb layers are inserte...Type-Ⅱ InAs/GaSb superlattiees made of 13 InAs monolayers （MLs） and 7 GaSb MLs are grown on GaSb substrates by solid source molecular beam epitaxy. To obtain lattice-matched structures, thin InSb layers are inserted between InAs and GaSb layers. We complete a series of experiments to investigate the influence of the InSb deposition time, Ⅴ/Ⅲ beam-equivalent pressure ratio and interruption time between each layer, and then characterize the superlattice （SL） structures with high-resolution x-ray diffraction and atomic force microscopy. The optimized growth parameters are applied to grow the 100-period SL structure, resulting in the full-width half-maximum of 29.55 arcsee for the first SL satellite peak and zero lattice-mismatch between the zero-order SL peak and the GaSb substrate peak.展开更多
We systematically investigate the influence of InSb interface(IF)engineering on the crystal quality and optical properties of strain-balanced InAs/GaSb type-Ⅱsuperlattices(T2SLs).The type-Ⅱsuperlattice structure is ...We systematically investigate the influence of InSb interface(IF)engineering on the crystal quality and optical properties of strain-balanced InAs/GaSb type-Ⅱsuperlattices(T2SLs).The type-Ⅱsuperlattice structure is 120 periods InAs(8 ML)/GaSb(6 ML)with different thicknesses of InSb interface grown by molecular beam epitaxy(MBE).The highresolution x-ray diffraction(XRD)curves display sharp satellite peaks,and the narrow full width at half maximum(FWHM)of the 0th is only 30-39 arcsec.From high-resolution cross-sectional transmission electron microscopy(HRTEM)characterization,the InSb heterointerfaces and the clear spatial separation between the InAs and GaSb layers can be more intuitively distinguished.As the InSb interface thickness increases,the compressive strain increases,and the surface“bright spots”appear to be more apparent from the atomic force microscopy(AFM)results.Also,photoluminescence(PL)measurements verify that,with the increase in the strain,the bandgap of the superlattice narrows.By optimizing the InSb interface,a high-quality crystal with a well-defined surface and interface is obtained with a PL wavelength of 4.78μm,which can be used for mid-wave infrared(MWIR)detection.展开更多
Type-Ⅱsuperlattice(T2SL)materials are the key element for infrared(IR)detectors.However,it is well known that the characteristics of the detectors with the T2SL layer are greatly affected by the strain developed duri...Type-Ⅱsuperlattice(T2SL)materials are the key element for infrared(IR)detectors.However,it is well known that the characteristics of the detectors with the T2SL layer are greatly affected by the strain developed during the growth process,which determines the performance of IR detectors.Therefore,great efforts have been made to properly control the strain effect and develop relevant analysis methods to evaluate the strain-induced dark current characteristics.In this work,we report the strain-induced dark current characteristics in InAs/GaSb T2SL MWIR photodetector.The overall strain of InAs/GaSb T2SL layer was analyzed by both high-resolution X-ray diffraction(HRXRD)and the dark current measured from the absorber layer at the elevated temperatures(≥110 K),where the major leakage current component is originated from the reduced minority carrier lifetime in the absorber layer.Our findings indicate that minority carrier lifetime increases as the tensile strain on the InAs/GaSb T2SL is more compensated by the compressive strain through‘InSb-like’interface,which reduces the dark current density of the device.Specifically,tensile strain compensated devices exhibited the dark current density of less than 2×10^-5 A/cm^2 at 120 K,which is more than one order of magnitude lower value compared to that of the device without tensile strain relaxation.展开更多
By optimizing theⅤ/Ⅲbeam-equivalent pressure ratio,a high-quality InAs/GaSb type-Ⅱsuperlattice material for the long-wavelength infrared(LWIR)range is achieved by molecular beam epitaxy(MBE).High-resolution x-ray d...By optimizing theⅤ/Ⅲbeam-equivalent pressure ratio,a high-quality InAs/GaSb type-Ⅱsuperlattice material for the long-wavelength infrared(LWIR)range is achieved by molecular beam epitaxy(MBE).High-resolution x-ray diffraction(HRXRD),atomic force microscopy(AFM),and Fourier transform infrared(FTIR)spectrometer are used to characterize the material growth quality.The results show that the full width at half maximum(FWHM)of the superlattice zero-order diffraction peak,the mismatching of the superlattice zero-order diffraction peak between the substrate diffraction peaks,and the surface roughness get the best results when the beam-equivalent pressure(BEP)ratio reaches the optimal value,which are 28 arcsec,13 arcsec,and 1.63?,respectively.The intensity of the zero-order diffraction peak is strongest at the optimal value.The relative spectral response of the LWIR detector shows that it exhibits a 100%cut-off wavelength of 12.6μm at 77 K.High-quality epitaxial materials have laid a good foundation for preparing high-performance LWIR detector.展开更多
We report a type-Ⅱ InAs/GaSb superlattice three-color infrared detector for mid-wave （MW）, long-wave （LW）, and very long-wave （VLW） detections. The detector structure consists of three contacts of NIPIN archite...We report a type-Ⅱ InAs/GaSb superlattice three-color infrared detector for mid-wave （MW）, long-wave （LW）, and very long-wave （VLW） detections. The detector structure consists of three contacts of NIPIN architecture for MW and LW detections, and hetero-junction NIP architecture for VLW detection. It is found that the spectral crosstalks can be significantly reduced by controlling the minority carriers transport via doping beryllium in the two active regions of NIPIN section. The crosstalk detection at MW, LW, and VLW signals are achieved by selecting the bias voltages on the device. At 77K, the cutoff wavelengths of the three-color detection are 5.3μm （at OmV）, 141μm （at 300mV） and 19μm （at -20mV） with the detectivities of 4.6xlO11 cm.Hzl/ZW-1, 2.3×10^10 cm.Hzl/2W-1, and 1.0×10^10cm.Hzl/2W-1 for MW, LW and VLW. The crosstalks of the MW channel, LW channel, and VLW channel are almost 0, 0.25, and 0.6, respectively.展开更多
A very long wavelength infrared（VLWIR） focal plane array based on In As/Ga Sb type-Ⅱ super-lattices is demonstrated on a Ga Sb substrate. A hetero-structure photodiode was grown with a 50% cut-off wavelength of 15...A very long wavelength infrared（VLWIR） focal plane array based on In As/Ga Sb type-Ⅱ super-lattices is demonstrated on a Ga Sb substrate. A hetero-structure photodiode was grown with a 50% cut-off wavelength of 15.2 μm, at 77 K.A 320×256 VLWIR focal plane array with this design was fabricated and characterized. The peak quantum efficiency without an antireflective coating was 25.74% at the reverse bias voltage of-20 mV, yielding a peak specific detectivity of 5.89×10^10cm·Hz^1/2·W^-1. The operability and the uniformity of response were 89% and 83.17%. The noise-equivalent temperature difference at 65 K exhibited a minimum at 21.4 mK, corresponding to an average value of 56.3 mK.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2015CB351902,2015CB932402 and 2012CB619203the National Natural Science Foundation of China under Grant Nos 61177070,11374295 and U1431231the National Key Research Program of China under Grant No 2011ZX01015-001
文摘Type-Ⅱ InAs/GaSb superlattiees made of 13 InAs monolayers （MLs） and 7 GaSb MLs are grown on GaSb substrates by solid source molecular beam epitaxy. To obtain lattice-matched structures, thin InSb layers are inserted between InAs and GaSb layers. We complete a series of experiments to investigate the influence of the InSb deposition time, Ⅴ/Ⅲ beam-equivalent pressure ratio and interruption time between each layer, and then characterize the superlattice （SL） structures with high-resolution x-ray diffraction and atomic force microscopy. The optimized growth parameters are applied to grow the 100-period SL structure, resulting in the full-width half-maximum of 29.55 arcsee for the first SL satellite peak and zero lattice-mismatch between the zero-order SL peak and the GaSb substrate peak.
基金Project supported by the Beijing Scholars Program(Grant No.74A2111113)the Research Project of Beijing Education Committee(Grant No.KM202111232019)+1 种基金the National Natural Science Foundation of China(Grant No.62105039)the Research Project of Beijing Information Science&Technology University(Grant No.2022XJJ07)
文摘We systematically investigate the influence of InSb interface(IF)engineering on the crystal quality and optical properties of strain-balanced InAs/GaSb type-Ⅱsuperlattices(T2SLs).The type-Ⅱsuperlattice structure is 120 periods InAs(8 ML)/GaSb(6 ML)with different thicknesses of InSb interface grown by molecular beam epitaxy(MBE).The highresolution x-ray diffraction(XRD)curves display sharp satellite peaks,and the narrow full width at half maximum(FWHM)of the 0th is only 30-39 arcsec.From high-resolution cross-sectional transmission electron microscopy(HRTEM)characterization,the InSb heterointerfaces and the clear spatial separation between the InAs and GaSb layers can be more intuitively distinguished.As the InSb interface thickness increases,the compressive strain increases,and the surface“bright spots”appear to be more apparent from the atomic force microscopy(AFM)results.Also,photoluminescence(PL)measurements verify that,with the increase in the strain,the bandgap of the superlattice narrows.By optimizing the InSb interface,a high-quality crystal with a well-defined surface and interface is obtained with a PL wavelength of 4.78μm,which can be used for mid-wave infrared(MWIR)detection.
基金supported by the research fund of Chungnam National University
文摘Type-Ⅱsuperlattice(T2SL)materials are the key element for infrared(IR)detectors.However,it is well known that the characteristics of the detectors with the T2SL layer are greatly affected by the strain developed during the growth process,which determines the performance of IR detectors.Therefore,great efforts have been made to properly control the strain effect and develop relevant analysis methods to evaluate the strain-induced dark current characteristics.In this work,we report the strain-induced dark current characteristics in InAs/GaSb T2SL MWIR photodetector.The overall strain of InAs/GaSb T2SL layer was analyzed by both high-resolution X-ray diffraction(HRXRD)and the dark current measured from the absorber layer at the elevated temperatures(≥110 K),where the major leakage current component is originated from the reduced minority carrier lifetime in the absorber layer.Our findings indicate that minority carrier lifetime increases as the tensile strain on the InAs/GaSb T2SL is more compensated by the compressive strain through‘InSb-like’interface,which reduces the dark current density of the device.Specifically,tensile strain compensated devices exhibited the dark current density of less than 2×10^-5 A/cm^2 at 120 K,which is more than one order of magnitude lower value compared to that of the device without tensile strain relaxation.
基金Project supported by the National Key Technology R&D Program of China(Grant Nos.2018YFA0209104,2018YFA0209102,2019YFA0705203,and2019YFA070104)the National Natural Science Foundation of China(Grant Nos.61790581,61274013,and 62004189)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB22).
文摘By optimizing theⅤ/Ⅲbeam-equivalent pressure ratio,a high-quality InAs/GaSb type-Ⅱsuperlattice material for the long-wavelength infrared(LWIR)range is achieved by molecular beam epitaxy(MBE).High-resolution x-ray diffraction(HRXRD),atomic force microscopy(AFM),and Fourier transform infrared(FTIR)spectrometer are used to characterize the material growth quality.The results show that the full width at half maximum(FWHM)of the superlattice zero-order diffraction peak,the mismatching of the superlattice zero-order diffraction peak between the substrate diffraction peaks,and the surface roughness get the best results when the beam-equivalent pressure(BEP)ratio reaches the optimal value,which are 28 arcsec,13 arcsec,and 1.63?,respectively.The intensity of the zero-order diffraction peak is strongest at the optimal value.The relative spectral response of the LWIR detector shows that it exhibits a 100%cut-off wavelength of 12.6μm at 77 K.High-quality epitaxial materials have laid a good foundation for preparing high-performance LWIR detector.
基金Supported by the National Basic Research Program of China under Grant Nos 2014CB643903,2013CB932904,2012CB932701 and 2011CB922201the National Special Funds for the Development of Major Research Equipment and Instruments of China under Grant No 2012YQ140005+7 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB01010200the China Postdoctoral Science Foundation-funded Project under Grant No 2014M561029the Program for New Century Excellent Talents in University under Grant No NCET-10-0066the National High-Technology Research and Development Program of China under Grant No 2013AA031502the Science and Technology Innovation Project of Harbin City under Grant No2011RFLXG006the National Natural Science Foundation of China under Grant Nos 61274013,U1037602,61306013,51202046,and 61290303the China Postdoctoral Science Foundation under Grant Nos 2012M510144 and 2013T60366the Fundamental Research Funds for the Central Universities under Grant Nos HIT.NSRIF.2013006 and HIT.BRETIII.201403
文摘We report a type-Ⅱ InAs/GaSb superlattice three-color infrared detector for mid-wave （MW）, long-wave （LW）, and very long-wave （VLW） detections. The detector structure consists of three contacts of NIPIN architecture for MW and LW detections, and hetero-junction NIP architecture for VLW detection. It is found that the spectral crosstalks can be significantly reduced by controlling the minority carriers transport via doping beryllium in the two active regions of NIPIN section. The crosstalk detection at MW, LW, and VLW signals are achieved by selecting the bias voltages on the device. At 77K, the cutoff wavelengths of the three-color detection are 5.3μm （at OmV）, 141μm （at 300mV） and 19μm （at -20mV） with the detectivities of 4.6xlO11 cm.Hzl/ZW-1, 2.3×10^10 cm.Hzl/2W-1, and 1.0×10^10cm.Hzl/2W-1 for MW, LW and VLW. The crosstalks of the MW channel, LW channel, and VLW channel are almost 0, 0.25, and 0.6, respectively.
基金supported by the National Basic Research Program of China(Grant Nos.2013CB932904 and 2011CB922201)the National Special Funds for the Development of Major Research Equipment and Instruments,China(Grant No.2012YQ140005)the National Natural Science Foundation of China(Grant Nos.61274013,61290303,and 61306013)
文摘A very long wavelength infrared（VLWIR） focal plane array based on In As/Ga Sb type-Ⅱ super-lattices is demonstrated on a Ga Sb substrate. A hetero-structure photodiode was grown with a 50% cut-off wavelength of 15.2 μm, at 77 K.A 320×256 VLWIR focal plane array with this design was fabricated and characterized. The peak quantum efficiency without an antireflective coating was 25.74% at the reverse bias voltage of-20 mV, yielding a peak specific detectivity of 5.89×10^10cm·Hz^1/2·W^-1. The operability and the uniformity of response were 89% and 83.17%. The noise-equivalent temperature difference at 65 K exhibited a minimum at 21.4 mK, corresponding to an average value of 56.3 mK.
