Hot phonon effect in mid-infrared HgTe/CdHgTe quantum wells evaluated by quasi-steady-state photoluminescence

Room-temperature photoluminescence (PL) spectra of intensely pumped HgTe/CdHgTe quantum well (QW) heterostructures emitting at around 5 μm wavelength have been investigated. Based on the model description of the PL spectra using a free-electron recombination band approach, effective electronic temperatures were determined depending on the excitation density. Within the quasi-steady-state approximation, we establish the balance between pump-induced heating of the electron gas in the QWs and phonon-mediated dissipation of this excess energy and deduce hot-phonon lifetime of ∼0.47 ps. Maximum operating temperatures for optically pumped HgTe/CdHgTe QW laser heterostructures emitting at around 5 μm are estimated depending on the excitation wavelength, and lasing at Peltier temperatures appears feasible for the pump wavelength of about 3 μm. Thus, the entire 3∼5 μm atmospheric transparency window can be potentially covered by thermoelectrically cooled HgCdTe-based laser sources.