The temperature-dependent behaviour of the bandgap of mid- and long-wavelength as well as dual-co... more The temperature-dependent behaviour of the bandgap of mid- and long-wavelength as well as dual-colour (mid-/long-wavelength) infrared detectors based on InAs/GaSb strained layer superlattices (SLSs) with p-i-n and nBn designs has been investigated with temperature-dependent absorption, photoluminescence and spectral response techniques. Values of Varshni parameters, zero temperature bandgap E0 and empirical coefficient alpha, were extracted and tabulated. The MWIR and LWIR superlattice detectors showed a temperature change of 0.325 meV K-1 and 0.282 meV K-1, respectively. These values are a factor of two lower than that of HgCdTe and InSb, making them attractive for higher operating temperatures.
Relationship between V/III beam equivalent pressure (BEP) flux ratios during the molecular beam e... more Relationship between V/III beam equivalent pressure (BEP) flux ratios during the molecular beam epitaxial (MBE) growth of long-wave infrared InAs/GaSb strained layer superlattice (SLS) material, crystalline quality of asgrown material, and devices' signal (responsivity) and noise (dark current) characteristics was investigated. It was found that the V/III ratio is a critical factor affecting the dark current, cut off wavelength and
ABSTRACT The development of InAsSb detectors based on the nBn design for the mid-wave infrared (M... more ABSTRACT The development of InAsSb detectors based on the nBn design for the mid-wave infrared (MWIR) spectral region is discussed. Comparisons of optical and electrical properties of InAsSb photodetectors with two different barrier material, namely, AlAs 0.15Sb0.75 (structure A) and AlAs0.10Sb0.9 (structure B) are reported. The dark current density in the AlAs0.15Sb0.85 is lower possibly due to the larger valence band offset. Clear room temperature spectral responses is observed and a specific detectivity (D*) of 1.4x1012 and 1.01x1012 cmHz1/2/W at 0.2 V, and a responsivity of 0.87 and 1.66 A/W under 0.2 V biasing at 77 K and 3.5 mum, assuming unity gain, was obtained for structures A and B, respectively.
Our group is investigating nBn detectors based on bulk InAs(1-x)Sb(x) absorber (n) and contacts (... more Our group is investigating nBn detectors based on bulk InAs(1-x)Sb(x) absorber (n) and contacts (n) with an AlAs(1-x)Sb(x) barrier (B). The wide-band-gap barrier material exhibits a large conduction band offset and small valence band offset with respect to the narrow-band-gap absorber material. An important matter to explore in this design is the barrier parameters (material, composition and doping concentration) and
ABSTRACT We present our efforts on development of high performance low noise, long-wave infrared ... more ABSTRACT We present our efforts on development of high performance low noise, long-wave infrared (LWIR) and multicolor detectors based on the InAs/GaSb strained layer material (SLS) material system. The LWIR SLS detector with PbIbN architecture showed improved performance over the conventional PIN design due to unipolar current blocking layers. At 77K and Vb=-0.25V, a responsivity of 1.8 A/W, dark current density of 1.2 mA/cm2, quantum efficiency of 23% and shot noise limited detectivity (D*) of 8.7×1010 Jones (lambdac = 10.8 mum) has been observed. Dual band response was registered with 50% cut-off wavelengths of 5mum and 10mum from an SLS detector with the pBp design. The responsivity equal to 1.6 A/W (at lambda = 5 mum and Vb = +0.4 V) and 1.8 A/W (at lambda = 9 mum and Vb = -0.7 V) for MWIR and LWIR absorbers was achieved with corresponding values of specific detectivity 5 x 1011 Jones and 2.6 x 1010 Jones, respectively. The maximum values of quantum efficiency were estimated to 41% (MWIR) and 25% (LWIR) at Vb = +0.4V and Vb = -0.7V. Moreover, the diffusion-limited behavior of dark current at higher temperatures was observed for the MWIR absorber for pBp detector. Finally, three-color response was registered from three contact device with nBn architecture for SWIR and MWIR and heterojunction PIbN architecture for LWIR detection (NbNbiP). At 77K, the cut-off wavelength for SWIR, MWIR and LWIR regions have been observed as 3.0 mum, 4.7 mum, and 10.1 mum respectively. At the same temperature, D* of 1.4 × 1010 Jones, 1.8 × 1010 Jones and 1.5 × 109 Jones for SWIR, MWIR and LWIR signals has been observed.
2009 34th International Conference on Infrared, Millimeter, and Terahertz Waves, 2009
As infrared focal plane arrays (FPAs) have evolved from the first generation of linear arrays to ... more As infrared focal plane arrays (FPAs) have evolved from the first generation of linear arrays to the second generation of small format staring arrays to the present "third-gen" devices, there is an increased emphasis on large area focal plane arrays with multicolor operation and higher operating temperature. In this paper, we will discuss how one needs to develop an increased
... Nutan Gautam, Ajit V. Barve, Stephen Myers, Brianna Klein, , Elena Plis, Mikhail Naydenkov,Ma... more ... Nutan Gautam, Ajit V. Barve, Stephen Myers, Brianna Klein, , Elena Plis, Mikhail Naydenkov,Maya N. Kutty, Ted Schuler-Sandy and S. Krishna Center for High Technology Materials, Dept of Electrical and Computer Engineering, University of New Mexico ... [2] GA Sai-Halasz, R ...
The device fabrication and integration of nanopatterned quantum dots (PQDs) are realized through ... more The device fabrication and integration of nanopatterned quantum dots (PQDs) are realized through the demonstration of a broad-area light-emitting diode with PQD active region. The device involves two growth processes, first to form PQDs by selective-area epitaxy on an SiO(2) mask and then to complete the device structure after mask removal. Linear current-voltage characteristics are observed with sharp turn-on, low leakage current and low forward resistance. Electroluminescence spectra show PQD intraband structure and low quenching of emission from 77 K to room temperature. Light-current measurements demonstrate external quantum efficiency per PQD comparable to self-assembled QDs, thus providing a possible route toward individually addressable single QD devices.
ABSTRACT We report a heterostructure bandgap engineered strained layer superlattice photodetector... more ABSTRACT We report a heterostructure bandgap engineered strained layer superlattice photodetector design for performance improvement for longwave infrared (LWIR) detection. At 77K, the dark current density of the reported device was at least two orders of magnitude lower than that of the conventional PIN superlattice photodiode. We have obtained a shot-noise limited detectivity of 8.7×1010cmHz1/2W−1 (λc=10.8μm), responsivity of 1.8A/W, 23% QE at 250mV of applied reverse bias. A three contact heterojunction bandgap engineered dual color detector was demonstrated with simultaneous detection of midwave and longwave infrared radiation. The design showed midwave responsivity of 0.93A/W and detectivity of 1.0×1011cmHz1/2W−1 (at 4μm) at 77K for Vb=−70mV. Longwave responsivity and detectivity of 1.5A/W and 2.42×1010cmHz1/2W−1 (at 10μm) were observed at −100mV of applied bias at 77K.
The temperature-dependent behaviour of the bandgap of mid- and long-wavelength as well as dual-co... more The temperature-dependent behaviour of the bandgap of mid- and long-wavelength as well as dual-colour (mid-/long-wavelength) infrared detectors based on InAs/GaSb strained layer superlattices (SLSs) with p-i-n and nBn designs has been investigated with temperature-dependent absorption, photoluminescence and spectral response techniques. Values of Varshni parameters, zero temperature bandgap E0 and empirical coefficient alpha, were extracted and tabulated. The MWIR and LWIR superlattice detectors showed a temperature change of 0.325 meV K-1 and 0.282 meV K-1, respectively. These values are a factor of two lower than that of HgCdTe and InSb, making them attractive for higher operating temperatures.
Relationship between V/III beam equivalent pressure (BEP) flux ratios during the molecular beam e... more Relationship between V/III beam equivalent pressure (BEP) flux ratios during the molecular beam epitaxial (MBE) growth of long-wave infrared InAs/GaSb strained layer superlattice (SLS) material, crystalline quality of asgrown material, and devices' signal (responsivity) and noise (dark current) characteristics was investigated. It was found that the V/III ratio is a critical factor affecting the dark current, cut off wavelength and
ABSTRACT The development of InAsSb detectors based on the nBn design for the mid-wave infrared (M... more ABSTRACT The development of InAsSb detectors based on the nBn design for the mid-wave infrared (MWIR) spectral region is discussed. Comparisons of optical and electrical properties of InAsSb photodetectors with two different barrier material, namely, AlAs 0.15Sb0.75 (structure A) and AlAs0.10Sb0.9 (structure B) are reported. The dark current density in the AlAs0.15Sb0.85 is lower possibly due to the larger valence band offset. Clear room temperature spectral responses is observed and a specific detectivity (D*) of 1.4x1012 and 1.01x1012 cmHz1/2/W at 0.2 V, and a responsivity of 0.87 and 1.66 A/W under 0.2 V biasing at 77 K and 3.5 mum, assuming unity gain, was obtained for structures A and B, respectively.
Our group is investigating nBn detectors based on bulk InAs(1-x)Sb(x) absorber (n) and contacts (... more Our group is investigating nBn detectors based on bulk InAs(1-x)Sb(x) absorber (n) and contacts (n) with an AlAs(1-x)Sb(x) barrier (B). The wide-band-gap barrier material exhibits a large conduction band offset and small valence band offset with respect to the narrow-band-gap absorber material. An important matter to explore in this design is the barrier parameters (material, composition and doping concentration) and
ABSTRACT We present our efforts on development of high performance low noise, long-wave infrared ... more ABSTRACT We present our efforts on development of high performance low noise, long-wave infrared (LWIR) and multicolor detectors based on the InAs/GaSb strained layer material (SLS) material system. The LWIR SLS detector with PbIbN architecture showed improved performance over the conventional PIN design due to unipolar current blocking layers. At 77K and Vb=-0.25V, a responsivity of 1.8 A/W, dark current density of 1.2 mA/cm2, quantum efficiency of 23% and shot noise limited detectivity (D*) of 8.7×1010 Jones (lambdac = 10.8 mum) has been observed. Dual band response was registered with 50% cut-off wavelengths of 5mum and 10mum from an SLS detector with the pBp design. The responsivity equal to 1.6 A/W (at lambda = 5 mum and Vb = +0.4 V) and 1.8 A/W (at lambda = 9 mum and Vb = -0.7 V) for MWIR and LWIR absorbers was achieved with corresponding values of specific detectivity 5 x 1011 Jones and 2.6 x 1010 Jones, respectively. The maximum values of quantum efficiency were estimated to 41% (MWIR) and 25% (LWIR) at Vb = +0.4V and Vb = -0.7V. Moreover, the diffusion-limited behavior of dark current at higher temperatures was observed for the MWIR absorber for pBp detector. Finally, three-color response was registered from three contact device with nBn architecture for SWIR and MWIR and heterojunction PIbN architecture for LWIR detection (NbNbiP). At 77K, the cut-off wavelength for SWIR, MWIR and LWIR regions have been observed as 3.0 mum, 4.7 mum, and 10.1 mum respectively. At the same temperature, D* of 1.4 × 1010 Jones, 1.8 × 1010 Jones and 1.5 × 109 Jones for SWIR, MWIR and LWIR signals has been observed.
2009 34th International Conference on Infrared, Millimeter, and Terahertz Waves, 2009
As infrared focal plane arrays (FPAs) have evolved from the first generation of linear arrays to ... more As infrared focal plane arrays (FPAs) have evolved from the first generation of linear arrays to the second generation of small format staring arrays to the present "third-gen" devices, there is an increased emphasis on large area focal plane arrays with multicolor operation and higher operating temperature. In this paper, we will discuss how one needs to develop an increased
... Nutan Gautam, Ajit V. Barve, Stephen Myers, Brianna Klein, , Elena Plis, Mikhail Naydenkov,Ma... more ... Nutan Gautam, Ajit V. Barve, Stephen Myers, Brianna Klein, , Elena Plis, Mikhail Naydenkov,Maya N. Kutty, Ted Schuler-Sandy and S. Krishna Center for High Technology Materials, Dept of Electrical and Computer Engineering, University of New Mexico ... [2] GA Sai-Halasz, R ...
The device fabrication and integration of nanopatterned quantum dots (PQDs) are realized through ... more The device fabrication and integration of nanopatterned quantum dots (PQDs) are realized through the demonstration of a broad-area light-emitting diode with PQD active region. The device involves two growth processes, first to form PQDs by selective-area epitaxy on an SiO(2) mask and then to complete the device structure after mask removal. Linear current-voltage characteristics are observed with sharp turn-on, low leakage current and low forward resistance. Electroluminescence spectra show PQD intraband structure and low quenching of emission from 77 K to room temperature. Light-current measurements demonstrate external quantum efficiency per PQD comparable to self-assembled QDs, thus providing a possible route toward individually addressable single QD devices.
ABSTRACT We report a heterostructure bandgap engineered strained layer superlattice photodetector... more ABSTRACT We report a heterostructure bandgap engineered strained layer superlattice photodetector design for performance improvement for longwave infrared (LWIR) detection. At 77K, the dark current density of the reported device was at least two orders of magnitude lower than that of the conventional PIN superlattice photodiode. We have obtained a shot-noise limited detectivity of 8.7×1010cmHz1/2W−1 (λc=10.8μm), responsivity of 1.8A/W, 23% QE at 250mV of applied reverse bias. A three contact heterojunction bandgap engineered dual color detector was demonstrated with simultaneous detection of midwave and longwave infrared radiation. The design showed midwave responsivity of 0.93A/W and detectivity of 1.0×1011cmHz1/2W−1 (at 4μm) at 77K for Vb=−70mV. Longwave responsivity and detectivity of 1.5A/W and 2.42×1010cmHz1/2W−1 (at 10μm) were observed at −100mV of applied bias at 77K.
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Papers by Maya Kutty