Wave-function engineering and absorption spectra in Si 0.16Ge0.84/Ge0.94Sn0.06/Si 0.16Ge0.84 strained on relaxed Si0.10Ge 0.90 type i quantum well

Abstract

We theoretically investigate germanium-tin alloy as a semiconductor for the design of near infrared optical modulators in which the Ge1-xSn x alloy is the active region. We have calculated the electronic band parameters for heterointerfaces between strained Ge1-xSnx and relaxed Si1-yGe y. Then, a type-I strain-compensated Si0.10Ge 0.90/Si0.16Ge0.84/Ge0.94Sn 0.06 quantum well heterostructure optimized in terms of compositions and thicknesses is studied by solving Schrödinger equation without and under applied bias voltage. The strong absorption coefficient (>1.5 × 104 cm-1) and the shift of the direct transition under large Stark effect at 3 V are useful characteristics for the design of optoelectronic devices based on compressively strained IV-IV heterostructures at near infrared wavelengths. © 2014 AIP Publishing LLC.