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Nonrelevant quantum levels limited laser dynamic in narrow-period terahertz quantum cascade lasers
- Source :
- Japanese Journal of Applied Physics. 61:102003
- Publication Year :
- 2022
- Publisher :
- IOP Publishing, 2022.
-
Abstract
- The fundamental challenges faced by terahertz quantum cascade lasers are the operations below room temperature, and the recent improved operating temperatures are actually based on the narrow-period designs (2-well resonant-phonon scheme). In this study, we address the critical effect of nonrelevant high-confined quantum levels on the laser threshold current in such designs, i.e. at high temperatures, the resonant-tunneling channels passing through neighboring periods via those levels can dominantly increase the laser threshold current. As a result, the laser dynamics significantly shrink to zero even at 270 K. The channels cannot be easily eliminated as they are derived from the specific configuration of a two-quantum-well periodic structure, in which the width of the period is narrow, and the nonrelevant levels from the lower-well are confined down in energy. It is reasonable to suppress the current flowing across those levels by narrowing the lower-well further, but an appropriate balance of its thickness is essential.
Details
- ISSN :
- 13474065 and 00214922
- Volume :
- 61
- Database :
- OpenAIRE
- Journal :
- Japanese Journal of Applied Physics
- Accession number :
- edsair.doi...........073dcfef7a28a0cee01458f19aec1263
- Full Text :
- https://doi.org/10.35848/1347-4065/ac8c0e