Area 4 : Electronics : Study of defect levels in InAs / InAsSb type - II superlattice using pressure - dependent photoluminescence

Number of Papers published in peer-reviewed journals: Number of Papers published in non peer-reviewed journals: Final Report: Research Area 4: Electronics: Study of defect levels in InAs/InAsSb type-II superlattice using pressuredependent photoluminescence Report Title We have performed pressure-dependent PL measurements on an InAs/InAs0.86 Sb0.14 T2SL structure. By fitting the measured peak energy shift and observing a quenching of the PL intensity we have determined a crossover pressure at which we believe the T2SL electron confined state reaches that of a defect level in the superlattice. This change in nature from a radiative to non-radiative recombination mechanism with pressure is confirmed from power dependent PL measurements. We also examined the thermal activation energies at ambient pressure and close to the crossover pressure. These results support and are consistent with the determined values for the pressure coefficients of the valence and conduction band edges of the structure and the defect level. As a result, these experiments provide strong evidence that the defect level is approximately 180 meV above the conduction band edge of InAs. Consequently, these findings explain why Ga-free T2SL structures have much longer minority carrier lifetimes, a highly desirable advantage for both mid-wave and long-wave IR photodetector applications. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or published that acknowledge ARO support from the start of the project to the date of this printing. List the papers, including journal references, in the following categories: (b) Papers published in non-peer-reviewed journals (N/A for none) (c) Presentations 07/07/2015 Received Paper 1.00 M. K. Lewis, A. D. Prins, Z. L. Bushell, S. J. Sweeney, S. Liu, Y.-H. Zhang. Evidence for a defect level above the conduction band edge of InAs/InAsSb type-II superlattices for applications in efficient infrared photodetectors, Applied Physics Letters, (04 2015): 0. doi: 10.1063/1.4919549