Electroluminescence from GeSn heterostructure pin diodes at the indirect to direct transition

Journal Article · Mon Mar 02 04:00:00 EST 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4913688· OSTI ID:22412738

Gallagher, J. D.; Menéndez, J. ^[1]; Senaratne, C. L.; Sims, P.; Kouvetakis, J. ^[2]; Aoki, T. ^[3]

---

1. Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States)
2. Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604 (United States)
3. LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, Arizona 85287- 1704 (United States)

The emission properties of GeSn heterostructure pin diodes have been investigated. The devices contain thick (400–600 nm) Ge{sub 1−y}Sn{sub y} i-layers spanning a broad compositional range below and above the crossover Sn concentration y{sub c} where the Ge{sub 1−y}Sn{sub y} alloy becomes a direct-gap material. These results are made possible by an optimized device architecture containing a single defected interface thereby mitigating the deleterious effects of mismatch-induced defects. The observed emission intensities as a function of composition show the contributions from two separate trends: an increase in direct gap emission as the Sn concentration is increased, as expected from the reduction and eventual reversal of the separation between the direct and indirect edges, and a parallel increase in non-radiative recombination when the mismatch strains between the structure components is partially relaxed by the generation of misfit dislocations. An estimation of recombination times based on the observed electroluminescence intensities is found to be strongly correlated with the reverse-bias dark current measured in the same devices.

• OSTI ID: 22412738
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 9 Vol. 106; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CONCENTRATION RATIO
DISLOCATIONS
ELECTROLUMINESCENCE
ENERGY GAP
GERMANIUM ALLOYS
HETEROJUNCTIONS
INTERFACES
LAYERS
RECOMBINATION
STRAINS
TIN ALLOYS