This SusChEM project utilizes nontoxic bismuth as a constituent to broaden and enhance the performance of III-V semiconductor alloys for a replacement of HgCdTe alloys. This work advances the materials science knowledge base of sustainable III-V bismides to enable novel devices needed for present and future engineering grand challenges, such as mid- and long-infrared lasers and detectors for homeland security and pollution detection and efficient infrared lasers and detectors for information and communication technology. Compared to HgCdTe alloys, III-V bismides are sustainable, safer, and more secure without toxic element mercury and the very rare element tellurium. This project integrates innovative and fundamental materials research and education, and brings together researchers and students with broad areas of expertise to study narrow bandgap III-V semiconductors alloyed with bismuth. The research findings guide the design and engineering of III-V bismuth superlattice materials and devices over a wide range of narrow bandgap energies, and could enable the development of devices with exceptional performance.
This research project alloys bismuth with arsenic in the group-V sublattice to develop III-V materials in the technological important 8-12 micrometer atmospheric transmission window. Specifically, the semi-metallic compound InBi is alloyed with conventional III-V bulk and superlattice materials to create alloys with significant and highly exploitable electrical and optical properties that outperform and replace HgCdTe. In particular, InAs/InAsBi and GaSb/InAsBi superlattices strain balanced and lattice matched at the GaSb lattice constant, offer the prospect of alloying technologically important 0.61-nm semiconductors with semiconducting InAsBi (Bi mole fractions < 7.3%) and semimetallic InAsBi (Bi mole fractions > 7.3%). These systems allow the growth of arbitrarily thick, coherently strained layers in the readily accessible GaSb lattice constant without misfit dislocations. Furthermore, the heterostructures offer an opportunity to design the topography of the band structure and thus allow studying quantum phase transitions of surface states using the effective bandgap of the superlattice as a tuning parameter.
