Enhanced Tensile Strain in P-doped Ge Films Grown by Molecular Beam Epitaxy Using GaP and Sb Solid Sources
- Resource Type
- Authors
- T. K. P. Luong; M. El Kurdi; V. Le Thanh; Philippe Boucaud; A. Ghrib
- Source
- Journal of Electronic Materials. 48:4674-4678
- Subject
- 010302 applied physics
Photoluminescence
Materials science
Solid-state physics
Dopant
business.industry
Doping
02 engineering and technology
021001 nanoscience & nanotechnology
Condensed Matter Physics
01 natural sciences
Electronic, Optical and Magnetic Materials
Active layer
0103 physical sciences
Materials Chemistry
Optoelectronics
Direct and indirect band gaps
Electrical and Electronic Engineering
0210 nano-technology
business
Electronic band structure
Molecular beam epitaxy
- Language
- ISSN
- 1543-186X
0361-5235
Ge emerges as a good candidate for the active layer in optoelectronic devices and is compatible with complementary metal oxide semiconductor technology. As the Ge band structure exhibits an indirect band gap with a small difference in energy between the direct and the indirect valleys (about 140 meV), the energy band structure can be modified by applying a tensile strain or by doping electrons into the film to turn Ge into a semiconductor material with a direct ban gap structure. In this work, Ge epilayers were grown on Si substrate by molecular beam epitaxy technique, and we show that the tensile strain value of the Ge epilayers increases by a factor of two by doping electrons into the films with two donor elements using GaP and Sb sources. The dopant concentration in Ge epilayers is 5.6 × 1019 at cm−3 for the P dopant and 6.4 × 1018 at cm−3 for the Sb dopant. The activated electron concentration was found to be up to 4.1019 cm−3 in the Ge film. A gain of photoluminescence (PL) intensity three times higher than the sample doped only with P atoms was obtained. This result contributes to the perspective that Ge films can be utilized in functional optoelectronic as well as photonic devices.