Quasi-Fermi Level Pinning in Interband Cascade Lasers
Author(s): Lin, YZ (Lin, Yuzhe); Li, L (Li, Lu); Huang, WX (Huang, Wenxiang); Yang, RQ (Yang, Rui Q.); Gupta, JA (Gupta, James A.); Zheng, WH (Zheng, Wanhua)
Source: IEEE JOURNAL OF QUANTUM ELECTRONICS Volume: 56 Issue: 4 Article Number: 2000810 DOI: 10.1109/JQE.2020.3003081 Published: AUG 2020
Abstract: A systematic study of the quasi-Fermi level pinning in various interband cascade lasers (ICLs) is reported. These ICLs, with either type-II or type-I quantum well active regions, cover the mid-infrared wavelength range from 3 to 6 mu m and can operate in continuous wave (cw) at room temperatures and above. It was found that the quasi-Fermi level can be pinned in many ICLs over a wide range of temperature, which is associated with an observed drop of differential resistance at threshold. For the first time, the quasi-Fermi level pinning was demonstrated in ICLs at room temperature. The temperature dependence of the quasi-Fermi level pinning in ICLs was also examined. A pinning factor is introduced to evaluate how well the quasi-Fermi level is pinned in ICLs with different configurations and lasing wavelengths. Also, it was found that the quasi-Fermi level pinning disappeared in some ICLs where an obvious drop of differential resistance could not be observed at the threshold. Furthermore, the quasi-Fermi level pinning was found to be correlated to the doping concentration in electron injectors in ICLs. Possible mechanisms and implications related to the quasiFermi level pinning are discussed.
Accession Number: WOS:000619207800001