Charge and thermal modeling of a semiconductor-based optical refrigerator
Abstract
Despite multiple attempts to achieve optical refrigeration in very high (99.5%) external quantum efficiency (EQE) GaAs, no cooling has been observed to date. In this study, we investigate optical refrigeration in GaAs by numerically solving the transient drift-diffusion equation coupled to Poisson's equation. The charge carrier distributions we obtain, together with the heat diffusion equation, allow us to observe the spatial and temporal evolution of cooling/heating within GaAs. Our results indicate that maximum cooling occurs at a laser intensity different from that which maximizes EQE. An 11-fold difference in intensity exists with a corresponding 6-fold difference in cooling power. We ultimately find that samples suspended in vacuum using a 250 μm SiO2 fiber cool to 88 K, starting from room temperature. These results emphasize the critical importance of choosing an appropriate laser excitation intensity to achieve optical refrigeration along with minimizing the conductive heat load on the refrigerator. Furthermore, results of this study are applicable towards analyzing the optical response of other optoelectronic systems where accurate charge and/or heat diffusion modeling is critical.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 29, 2018
- Source ID
- 10.1063/1.5049376
Entities
People
- Boldizsár Jankó
- Masaru Kuno
- Shubin Zhang
- Yurii V. Morozov
Organizations
- Air Force Office of Scientific Research
- University of Notre Dame