High n-Type Doping in Ge for Optical Gain and Lasing

Abstract:

We review two ex-situ doping methods to achieve high n-type doping up to mid-10¹⁹ cm^-3 in Ge-on-Si thin films. For both, delta doping and ion implantation, rapid thermal annealing is used to diffuse phosphorus from a diffusion source into the single crystal Ge layer. The diffusion mechanism is studied and we find that dopant enhanced diffusion in in-situ doped Ge attributes to the high doping level. A band gap narrowing effect is observed in highly doped n-type Ge through photoluminescence measurements by determining the photoluminescence peak shift. An empirical linear expression of the direct band gap narrowing shift with carrier concentration is proposed.

• Periodical: Solid State Phenomena (Volumes 205-206)
• Pages: 394-399
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.205-206.394
• Online since: October 2013
• Authors: Yan Cai, Jurgen Michel
• Keywords: Band Gap Narrowing, Diffusion, Germanium, n-Type Doping, Photoluminescence (PL)

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