The objective of this research is to employ graphene transparent electrical contacts atop mid-infrared semiconductor lasers to determine the fundamental physical mechanisms that critically limit high-temperature operation. The approach is to use antimonide-based semiconductor lasers as the platform to test optical transparency, electrical conductivity, and the heat dissipation efficacy of single and few-layer graphene. Both multi-domain and single-crystal graphene monolayers will be compared as well as bilayers and trilayers with non-Bernal and Bernal AB stacking. The capability graphene will provide to simultaneously optically pump and electrically bias laser devices will enable precise measurements of carrier concentrations above threshold in order to elevate the characteristic temperature of these promising 3?5 µm devices above 100 K. In addition to the high optical transmission and excellent electrical properties of graphene that could lead to lower thresholds, higher output powers, and higher operating temperatures in mid-infrared emitters, graphene has demonstrated excellent potential for heat dissipation, which will be studied and related to its potential as a single-atom-thick heat dissipater in electronic devices in general. Thin, transparent contacts with high mobility and excellent heat dissipation may have extensive applications in optoelectronic devices, including light emitting diodes, lasers, transistors, and other devices that require good thermal management while minimizing the size of the heat dissipating layer. Important applications of mid-infrared devices include environmental monitoring, countermeasures, and free space communications. The PIs will continue to involve women, high school students, and undergraduates in the research and to reach out to K-12 students and teachers.
