Wave-function engineering and absorption spectra in Si0.16Ge0.84/Ge0.94Sn0.06/Si0.16Ge0.84 strained on relaxed Si0.10Ge0.90 type I quantum well

We theoretically investigate germanium-tin alloy as a semiconductor for the design of near infrared optical modulators in which the Ge1−xSnx alloy is the active region. We have calculated the electronic band parameters for heterointerfaces between strained Ge1−xSnx and relaxed Si1−yGey. Then, a type-I strain-compensated Si0.10Ge0.90/Si0.16Ge0.84/Ge0.94Sn0.06 quantum well heterostructure optimized in terms of compositions and thicknesses is studied by solving Schrodinger 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.