Mid-infrared emission from direct Ge0.922Sn0.078 alloy in strained Ge/Ge0.922Sn0.078/Ge LEDs

Author

Shieh, T.-H. ; Hung, K.-M. ; Hsu, Y.-H. ; Wang, W.-H. ; Lee, R.-S. ; Hu, H.-Y. ; Wu, K.-Y. ; Cheng, Han-Hsiang

Author_Institution

Dept. of Electro-Opt. Eng., Kun Shan Univ., Tainan, Taiwan

Volume

2

fYear

2014

fDate

26-28 April 2014

Firstpage

960

Lastpage

962

Abstract

Density functional theory with SQS-32 (Special Quasi-random Structures with 32-atom super-cell) configuration is applied to study the energy-gap properties of strained GeSn alloys. The calculation results show that the direct-indirect crossover occurs at the mole fraction of ~ 6%. The energies of direct and indirect gaps at x ~ 0.075 are well agreement to recent experiments. The calculated emitting powers for these gaps reveal that the lowest peak energy in electroluminescence experiment of strained Ge/Ge_0.922Sn_0.078/Ge LED mainly originates in the direct gap rather than indirect. It is in contrast to the recent experimental report. Our results show that the strained Ge_0.922Sn_0.078 is direct gap.

Keywords

density functional theory; electroluminescence; germanium; germanium alloys; light emitting diodes; tin alloys; Ge-Ge_0.922Sn_0.078-Ge; Ge_0.922Sn_0.078; LED; SQS-32; density functional theory; electroluminescence; energy-gap properties; mid-infrared emission; special quasirandom structures; strained GeSn alloys; Correlation; Density functional theory; Educational institutions; Light emitting diodes; Strain; Tin; GeSn alloy; density functional theory; direct gap;

fLanguage

English

Publisher

ieee

Conference_Titel

Information Science, Electronics and Electrical Engineering (ISEEE), 2014 International Conference on

Conference_Location

Sapporo

Print_ISBN

978-1-4799-3196-5

Type

conf

DOI

10.1109/InfoSEEE.2014.6947810

Filename

6947810