Systematic study of GeSn heterostructure-based light-emitting diodes towards mid-infrared applications
Abstract
Temperature-dependent characteristics of GeSn light-emitting diodes with Sn composition up to 9.2% have been systematically studied. Such diodes were based on Ge/GeSn/Ge double heterostructures (DHS) that were grown directly on a Si substrate via a chemical vapor deposition system. Both photoluminescence and electroluminescence spectra have been characterized at temperatures from 300 to 77 K. Based on our theoretical calculation, all GeSn alloys in this study are indirect bandgap materials. However, due to the small energy separation between direct and indirect bandgap, and the fact that radiative recombination rate greater than non-radiative, the emissions are mainly from the direct Γ-valley to valence band transitions. The electroluminescence emissions under current injection levels from 102 to 357 A/cm2 were investigated at 300 K. The monotonic increase of the integrated electroluminescence intensity was observed for each sample. Moreover, the electronic band structures of the DHS were discussed. Despite the indirect GeSn bandgap owing to the compressive strain, type-I band alignment was achieved with the barrier heights ranging from 11 to 47 meV.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 13, 2016
- Source ID
- 10.1063/1.4958337
Entities
People
- Aboozar Mosleh
- Baohua Li
- Greg Sun
- Hameed Naseem
- Joe Margetis
- John Tolle
- Mansour Mortazavi
- Murtadha Alher
- Richard Soref
- Sattar Al-Kabi
- Seyed Amir Ghetmiri
- Shui-Qing Yu
- Thach Pham
- Wei Dou
- Wei Du
- Yiyin Zhou
Organizations
- Air Force Office of Scientific Research
- National Science Foundation
- University of Arkansas
- University of Arkansas at Pine Bluff
- University of Massachusetts Boston
- University of Wasit