Computational design of compounds for monolithic integration in optoelectronics

A class of semiconductors is introduced and their physical properties are examined using both ab initio total-energy calculations and quasiparticle GW calculations. These compounds are designed to address problems of lattice-constant mismatch and polarity mismatch that are common issues in heteroepitaxial growth of III-V alloys on silicon substrates. A variety of configurations of these materials is explored. It is found that their lattice constants and band gaps fall into a region of phase space different from that of conventional semiconductors, making them potential candidates for the basis of optical devices—infrared emitters and detectors. A particular suitable configuration is identified that is lattice-constant matched to Si and has a direct band gap of 0.8 eV. This gap corresponds to the canonical wavelength of $1.5\mu \mathrm{m}$ in optoelectronics. Thus this material could ultimately enable tractable monolithic integration of optics with electronics. The characteristics of this particular configuration are examined in depth, including its temperature dependence, its bulk energetics, and its growth energetics. The results of these analyses indicate that fabrication of these compounds using heteroepitaxial growth techniques should be feasible.