Effect of pressure on electrical properties of short period InAs/GaSb superlattice (original) (raw)
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Transport measurements on InAs/GaSb superlattice structures for mid-infrared photodiode
Journal of Physics: Conference Series, 2009
In this communication, we report on electrical transport measurements of nonintentionally doped InAs/GaSb Superlattice structures grown by Molecular Beam Epitaxy. Resistivity and Hall Effect measurements were performed on two samples, corresponding to the same SL structure that has been grown on two different substrates: one on semi-insulating GaAs substrate, another on n-type GaSb substrate. To carry out the electrical measurements, the conducting GaSb substrate of the second sample has been removed. The study were performed in the temperature range 77-300K, for magnetic fields of 0.38 T.. The both samples exhibited a change in type of conductivity from p-type at low temperature to n-type near room temperature.
Electrical properties of short period InAs/GaSb superlattice
physica status solidi (c), 2007
Electrical properties in the temperature range between 80K and 300K of type-II short period InAs/GaSb superlattice (SL) photodiode are reported. Resistivity and Hall measurements have been carried out on a 300 periods unintentionally doped SL grown on semi-insulating GaAs substrate while capacitance-voltage and current-voltage measurements have been performed on the same SL structure elaborated on n-type GaSb substrate. Whatever the electrical investigations, the behaviour of the InAs/GaSb SL versus temperature exhibited a reproducible change in type of conductivity. The SL is n-type at high temperatures range with n(300K) = 6x10 16 cm -3 whereas it is p-type at low temperatures with p(100K) = 2x10 16 cm -3 . This versatile change in type of conductivity is attributed to the presence of inserted InSb layer at the InAs-GaSb interface.
Electronic properties of InAs/GaSb superlattice detectors to evaluate high-temperature operation
Quantum Sensing and Nanophotonic Devices VII, 2010
Electrical properties of non-intentionally doped (nid) InAs/GaSb Superlattice (SL) structures and p-nid-n detectors grown by Molecular Beam Epitaxy on GaSb substrate are reported. The SL structures were made of 600 periods of 8 InAs monolayers (MLs) and 8 GaSb MLs, for a total thickness of 3μm. This structure exhibited a cutoff wavelength in the midwave infrared (MWIR) domain, near 4.7µm at 80K. Electrical transport measurements, based on resistivity and Hall Effect measurements, were performed on SL structure after removing the conducting GaSb substrate with an appropriate technological process. Carrier concentrations and mobilities carried out as a function of temperature (77-300K) for magnetic fields in the 0-1 Tesla range are analyzed. A change in type of conductivity is observed. The nid SL layers is p-type at liquid Nitrogen temperature while is n-type at room temperature. These results are completed with diode characterizations based on current-voltage (I-V) and capacitance-voltage (C-V) measurements performed on p-nidn devices with identical InAs/GaSb SL active zone.
Nanoscale Research Letters, 2018
In the present work, we report on the in-plane electrical transport properties of midwave (MWIR) and longwave infrared (LWIR) InAs/GaSb type-II superlattices (T2SLs) grown by molecular beam epitaxy (MBE) system on GaAs (001) substrate. The huge lattice mismatch between the T2SL and GaAs substrate is reduced by the growth of GaSb buffer layer based on interfacial misfit array (IMF) technique. In order to compensate the strain in the InAs/GaSb T2SL, we utilized a special shutters sequence to get InSb-like and GaAs-like interfaces. It is found that the MWIR InAs/GaSb T2SL exhibits a pand n-type conduction at low and high temperatures, respectively. Interestingly, the conduction change temperature is observed to be dependent on the growth temperature. On the other hand, LWIR T2SL conduction is dominated only by electrons. It is important to note that the dominant scattering mechanism in LWIR T2SL at low temperatures is the interface roughness scattering mechanism.
Investigation of impurities in type-II InAs/GaSb superlattices via capacitance-voltage measurement
Capacitance-voltage measurement was utilized to characterize impurities in the non-intentionally doped region of Type-II InAs/GaSb superlattice p-i-n photodiodes. Ionized carrier concentration versus temperature dependence revealed the presence of a kind of defects with activation energy below 6 meV and a total concentration of low 10 15 cm À3 . Correlation between defect characteristics and superlattice designs was studied. The defects exhibited a p-type behavior with decreasing activation energy as the InAs thickness increased from 7 to 11 monolayers, while maintaining the GaSb thickness of 7 monolayers. With 13 monolayers of InAs, the superlattice became n-type and the activation energy deviated from the p-type trend. V C 2013 AIP Publishing LLC.
Infrared Physics & Technology, 2014
Herein, we report a type II InAs/GaSb superlattice structure (SLS) grown on GaSb (100) substrates by molecular beam epitaxy (MBE) and its electrical characterization for mid-wavelength infrared detection. A GaSb buffer layer was grown under optimized SLS growth conditions, which can decrease the occurrence of defects for similar pyramidal structures. The complications associated with these conditions include oxide desorption of the substrate, growth temperature of the SLS, the V/III ratio during superlattice growth and the shutter sequence. High-resolution X-ray diffraction (HRXRD) shows the sixth satellite peak, and the period of the SLS was 52.9 Å. The atomic force microscopy (AFM) images indicated that the roughness was less than 2.8 nm. High-resolution transmission electron microscopy (HRTEM) images indicated that the SLS contains few structural defects related to interface dislocations or strain relaxation during the growth of the superlattice layer. The photoresponse spectra indicated that the cutoff wavelength was 4.8 µm at 300 K. The SLS photodiode surface was passivated by a zinc sulfide (ZnS) coating after anodic sulfide.
Growth and characterization of InAs/GaSb photoconductors for long wavelength infrared range
Applied Physics Letters, 1997
In this letter we report the molecular beam epitaxial growth and characterization of InAs/GaSb superlattices grown on semi-insulating GaAs substrates for long wavelength infrared detectors. Photoconductive detectors fabricated from the superlattices showed photoresponse up to 12 m and peak responsivity of 5.5 V/W with Johnson noise limited detectivity of 1.33ϫ10 9 cm Hz 1/2 /W at 10.3 m at 78 K. © 1997 American Institute of Physics. ͓S0003-6951͑97͒03236-1͔
Interface analysis of InAs/GaSb superlattice grown by MBE
(2007) Journal of Crystal Growth, 301-302 (SPEC. ISS.), pp. 889-892.
We report on the structural characterization of short period type-II InAs/GaSb superlattices (SLs) adapted for mid-infrared detection. These structures, grown by molecular beam epitaxy (MBE) on n-type GaSb substrates, are made up of 10 InAs monolayers (MLs) and 10 GaSb MLs and a strain balanced condition is obtained by inserting an InSb ML at the interface between InAs and GaSb in each superlattice's period. From cross-sectional transmission electron microscopy (TEM) measurements, the interface structure is analysed in detail. Very homogeneous and smooth InAs and GaSb layers all over a 50 periods SL structure are observed and high-resolution images bring out the InSb ML inserted between InAs and GaSb. Room temperature absorbance spectroscopy measurements have been performed on strain-compensated SLs including 50, 100, 300 and 400 periods, for a total absorption zone thickness of 0.32, 0.64, 1.92 and 2.56 μm, respectively. The spectra display reproducible and well-defined features with an absorption coefficient varying between 2×10 3 and 4×10 3 cm -1 in the 3-5 μm mid-infrared domain, a sign of high-quality samples suitable for detection.
Temperature dependence performances of InAs/GaSb superlattice photodiode
Infrared Physics & Technology, 2011
In this communication we report on temperature dependence performances of short period InAs/GaSb pin superlattice (SL) photodiode grown by Molecular Beam Epitaxy on p-type GaSb substrate. SL symmetrical structure with 3 lm thick active region, adapted for detection in the MWIR domain with cutoff wavelength varying from 4.6 lm to 5.5 lm in the temperature range 80-300 K, was processed in mesa photodiode in order to perform dark current measurements as a function of temperature. Extracted from current-voltage characteristics, R 0 A products above 1 Â 10 6 X cm 2 at 80 K and around 0.15 X cm 2 at 200 K were measured, and the quantitative analysis of the J-V curves allowed us to identify the dominant dark current mechanism in each operating temperature range. As a result, SL photodiode is dominated by generation-recombination (GR) processes at low temperature and becomes diffusion limited above 140 K. Such results are discussed and minority carrier lifetimes were extracted from J-V curve fitting.