Title :
First-principles study of light emission from silicon and germanium due to direct transitions
Author :
Suwa, Yuji ; Saito, Shin-ichi
Author_Institution :
Photonics Electron. Technol. Res. Assoc., Tsukuba, Japan
Abstract :
Light emissions from silicon and germanium due to direct transitions are studied based on first principles calculations. We found that direct transition occurs in a ultra-thin silicon film efficiently due to a valley-projection and quantum-confinement effect. While the same mechanism works in a ultra-thin germanium film, we found that utilizing a small electron pocket at Γ, which exists in a bulk germanium, is more effective to make an efficient light source. The effects of strain and electron doping are also discussed in detail.
Keywords :
ab initio calculations; carrier density; elemental semiconductors; energy gap; germanium; photoluminescence; semiconductor doping; semiconductor thin films; silicon; tensile strength; Ge; Si; carrier density; direct transition; efficient light source; electron doping; energy gap; first-principles calculation; light emission; quantum confinement effect; small electron pocket; strain effects; tensile strain; ultrathin germanium film; ultrathin silicon film; valley projection; Atom optics; Charge carrier density; Electron optics; Germanium; Integrated optics; Silicon; Tensile strain;
Conference_Titel :
Group IV Photonics (GFP), 2011 8th IEEE International Conference on
Conference_Location :
London
Print_ISBN :
978-1-4244-8338-9
DOI :
10.1109/GROUP4.2011.6053770
