RESUMEN
We theoretically study and experimentally demonstrate a pseudomorphic Ge/Ge0.92Sn0.08/Ge quantum-well microdisk resonator on Ge/Si (001) as a route toward a compact GeSn-based laser on silicon. The structure theoretically exhibits many electronic and optical advantages in laser design, and microdisk resonators using these structures can be precisely fabricated away from highly defective regions in the Ge buffer using a novel etch-stop process. Photoluminescence measurements on 2.7 µm diameter microdisks reveal sharp whispering-gallery-mode resonances (Q > 340) with strong luminescence.
RESUMEN
We present a new etch chemistry that enables highly selective dry etching of germanium over its alloy with tin (Ge(1-x)Sn(x)). We address the challenges in synthesis of high-quality, defect-free Ge(1-x)Sn(x) thin films by using Ge virtual substrates as a template for Ge(1-x)Sn(x) epitaxy. The etch process is applied to selectively remove the stress-inducing Ge virtual substrate and achieve strain-free, direct band gap Ge0.92Sn0.08. The semiconductor processing technology presented in this work provides a robust method for fabrication of innovative Ge(1-x)Sn(x) nanostructures whose realization can prove to be challenging, if not impossible, otherwise.
