Compositional control of the mixed anion alloys in gallium-free InAs/InAsSb superlattice materials for infrared sensing

Gallium (Ga)-free InAs/InAsSb superlattices (SLs) are being actively explored for infrared detector applications due to the long minority carrier lifetimes observed in this material system. However, compositional and dimensional changes through antimony (Sb) segregation during InAsSb growth can significantly alter the detector properties from the original design. At the same time, precise compositional control of this mixed-anion alloy system is the most challenging aspect of Ga-free SL growth. In this study, the authors establish epitaxial conditions that can minimize Sb surface segregation during growth in order to achieve high-quality InAs/InAsSb SL materials. A nominal SL structure of 77 Å InAs/35 Å InAs0.7Sb0.3 that is tailored for an approximately six-micron response at 150 K was used to optimize the epitaxial parameters. Since the growth of mixed-anion alloys is complicated by the potential reaction of As2 with Sb surfaces, the authors varied the deposition temperature (Tg) under a variety of Asx flux conditions in order to control the As2 surface reaction on a Sb surface. Experimental results reveal that, with the increase of Tg from 395 to 440 °C, Sb-mole fraction x in InAs1-xSbx layers is reduced by 21 %, under high As flux condition and only by 14 %, under low As flux condition. Hence, the Sb incorporation efficiency is extremely sensitive to minor variations in epitaxial conditions. Since a change in the designed compositions and effective layer widths related to Sb segregation disrupts the strain balance and can significantly impact the long-wavelength threshold and carrier lifetime, further epitaxial studies are needed in order to advance the state-of-the-art of this material system.

[1]  L. Grazulis,et al.  Growth optimization studies to develop InAs/GaInSb superlattice materials for very long wavelength infrared detection , 2015 .

[2]  Michael E. Flatte,et al.  Modeling of very long infrared wavelength InAs/GaInSb strained layer superlattice detectors , 2002, SPIE Optics + Photonics.

[3]  John F. Klem,et al.  Monolayer-by-monolayer compositional analysis of InAs/InAsSb superlattices with cross-sectional STM , 2015 .

[4]  Brian R. Bennett,et al.  Effects of As2 versus As4 on InAs/GaSb heterostructures: As-for-Sb exchange and film stability , 2001 .

[5]  Gail J. Brown,et al.  Control of anion incorporation in the molecular beam epitaxy of ternary antimonide superlattices for very long wavelength infrared detection , 2015 .

[6]  Hui Li,et al.  Long-wave infrared nBn photodetectors based on InAs/InAsSb type-II superlattices , 2012 .

[7]  Darryl L. Smith,et al.  Proposal for strained type II superlattice infrared detectors , 1987 .

[8]  T. F. Boggess,et al.  Time-resolved optical measurements of minority carrier recombination in a mid-wave infrared InAsSb alloy and InAs/InAsSb superlattice , 2012 .

[9]  G. Belenky,et al.  Growth of type II strained layer superlattice, bulk InAs and GaSb materials for minority lifetime characterization , 2011 .

[10]  Krishnamurthy Mahalingam,et al.  Growth of short-period InAs∕GaSb superlattices , 2006 .

[11]  Krishnamurthy Mahalingam,et al.  Quantitative analysis of strain distribution in InAs/InAs1−xSbx superlattices , 2013 .

[12]  Krishnamurthy Mahalingam,et al.  Band gap tuning of InAs∕GaSb type-II superlattices for mid-infrared detection , 2004 .

[13]  S. Krishna,et al.  InAs/GaSb Superlattice Detectors Operating at Room Temperature , 2006, IEEE Journal of Selected Topics in Quantum Electronics.

[14]  Krishnamurthy Mahalingam,et al.  Exploring optimum growth window for high quality InAs/GaInSb superlattice materials , 2013, Defense, Security, and Sensing.

[15]  Andrew G. Glen,et al.  APPL , 2001 .

[16]  Thomas E. Vandervelde,et al.  Progress in Infrared Photodetectors Since 2000 , 2013, Sensors.

[17]  Bruno Ullrich,et al.  Pushing the envelope to the maximum : Short-period InAs/GaSb type-II superlattices for mid-infrared detectors , 2006 .

[18]  Gregory Belenky,et al.  Carrier lifetime measurements in short-period InAs/GaSb strained-layer superlattice structures , 2009 .

[19]  John F. Klem,et al.  Effects of layer thickness and alloy composition on carrier lifetimes in mid-wave infrared InAs/InAsSb superlattices , 2014 .

[20]  Krishnamurthy Mahalingam,et al.  Optimum growth window for InAs/GaInSb superlattice materials tailored for very long wavelength infrared detection , 2014 .

[21]  Gail J. Brown,et al.  Effect of interfaces and the spin-orbit band on the band gaps of InAs/GaSb superlattices beyond the standard envelope-function approximation , 2004 .

[22]  Krishnamurthy Mahalingam,et al.  Impact of growth temperature on InAs/GaInSb strained layer superlattices for very long wavelength infrared detection , 2012 .