Abstract
Conventional quantum cascade lasers (QCLs) are composed of a superlattice structure with identical compositions of quantum wells and barriers. In this structure, the energy difference between the upper laser state and the upper energy states leads to a significant leakage current from the upper laser state to the continuum band at room temperature. As a result, the operating characteristics (i.e., T0 and T1) of QCLs at roon temperature are poor. In order to suppress carrier leakage in the active region, we suggest a QCL structure employing a tapered-active region (TA). Importantly, the alloy composition of the quantum wells and barriers are varied in this structure. In order to compare the operating characteristics of conventional QCL' s at room temperature with those of TA QCLs, we have examined the leakage current density at various temperatures by using a KP simulation. A significant reduction in the carrier leakage is found for the TA QCL structure. The reduction in the carrier leakage may improve the output power and the wallplug efficiency of the QCL during room-temperature, continuous-wave operation.
Original language | English |
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Pages (from-to) | 472-477 |
Number of pages | 6 |
Journal | New Physics: Sae Mulli |
Volume | 66 |
Issue number | 4 |
DOIs | |
State | Published - Apr 2016 |
Keywords
- Mid-infrared
- Quantum cascade laser
- Quantum well
- Tapered-active region