Band-gap narrowing determination by photoluminescence on strained B-doped Si0.82Ge0.18 layers grown on Si

Abstract
This work reports on photoluminescence (PL) characterization of heavy boron‐doped SiGe(p+)/Si(p) heterostructures and Si(p+)/Si(p) pseudoheterostructures grown by rapid thermal chemical vapor deposition. For the pseudoheterostructures, the band‐gap narrowing is measured in the 4×1018–1.5×1019 cm−3 doping level range in very good agreement with bulk silicon results. The band‐gap narrowing of SiGe strained layers has been determined for the first time, by means of PL measurements on boron‐doped Si0.82Ge0.18 strained alloy up to 4×1019 cm−3. The reduced band gap of the Si0.82Ge0.18 alloy is deduced, taking into account both strain and heavy doping effects and compared to band‐gap narrowing found in Si.