Evidence for a defect level above the conduction band edge of InAs/InAsSb type-II superlattices for applications in efficient infrared photodetectors

A. D. Prins, M. K. Lewis, Z. L. Bushell, S. J. Sweeney, S. Liu, Yong-Hang Zhang

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We report pressure-dependent photoluminescence (PL) experiments under hydrostatic pressures up to 2.16 GPa on a mid-wave infrared InAs/InAs<inf>0.86</inf>Sb<inf>0.14</inf> type-II superlattice (T2SL) structure at different pump laser excitation powers and sample temperatures. The pressure coefficient of the T2SL transition was found to be 93 ± 2 meV·GPa<sup>-1</sup>. The integrated PL intensity increases with pressure up to 1.9 GPa then quenches rapidly indicating a pressure induced level crossing with the conduction band states at ∼2 GPa. Analysis of the PL intensity as a function of excitation power at 0, 0.42, 1.87, and 2.16 GPa shows a clear change in the dominant photo-generated carrier recombination mechanism from radiative to defect related. From these data, evidence for a defect level situated at 0.18 ± 0.01 eV above the conduction band edge of InAs at ambient pressure is presented. This assumes a pressure-dependent energy shift of -11 meV·GPa<sup>-1</sup> for the valence band edge and that the defect level is insensitive to pressure, both of which are supported by an Arrhenius activation energy analysis.

Original languageEnglish (US)
Article number171111
JournalApplied Physics Letters
Issue number17
Publication statusPublished - Apr 27 2015


ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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