Investigation of Trap States in Mid-Wavelength Infrared Type II Superlattices Using Time-Resolved Photoluminescence

• Published in: Journal of electronic materials 2013-11, Vol.42 (11), p.3203-3210
• Main Authors: Connelly, Blair C., Metcalfe, Grace D., Shen, Hongen, Wraback, Michael, Canedy, Chadwick L., Vurgaftman, Igor, Melinger, Joseph S., Affouda, Chaffra A., Jackson, Eric M., Nolde, Jill A., Meyer, Jerry R., Aifer, Edward H.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electrical engineering; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronics and Microelectronics; Exact sciences and technology; Instrumentation; Luminescence; Materials Science; Optical and Electronic Materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other semiconductors; Photoluminescence; Physics; Solid State Physics; Specific materials; Spectrum analysis; Structure and morphology; thickness; Surface and interface electron states; Surface states, band structure, electron density of states; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-013-2759-9

Time-resolved photoluminescence (TRPL) spectroscopy is used to study the minority-carrier lifetime in mid-wavelength infrared, n -type, InAs/Ga 1− x In x Sb type II superlattices (T2SLs) and investigate the recombination mechanisms and trap states that currently limit their performance. Observation of multiple exponential decays in the intensity-dependent TRPL data indicates trap saturation due to the filling then emptying of trap states and different Shockley–Read–Hall (SRH) lifetimes for minority and majority carriers, with τ maj  ( τ n 0 ) ≫  τ min  ( τ p 0 ). Simulation of the photoluminescence transient captures the qualitative behavior of the TRPL data as a function of temperature and excess carrier density. A trap state native to Ga 1− x In x Sb is identified from the low-injection temperature-dependent TRPL data and found to be located below the intrinsic Fermi level of the superlattice, approximately 60 ± 15 meV above the valence-band maximum. Low-temperature TRPL data show a variation of the minority-carrier SRH lifetime, τ p 0 , over a set of InAs/Ga 1− x In x Sb T2SLs, where τ p 0 increases as x is varied from 0.04 to 0.065 and the relative layer thickness of Ga 1− x In x Sb is increased by 31%.