Electron transport process in quantum cascade intersubband semiconductor lasers

Abstract

Detailed self-consistent calculations have been performed of the electron transport and capture aspects of the dynamics of electrically pumped quantum cascade intersubband semiconductor lasers. Specific attention is given to the dependence of the characteristic carrier relaxation times on carrier temperature and density at different applied biases. We have found that the capture and intersubband relaxation times oscillate with increasing electric field. Correlative oscillations can be observed when electron temperature and electron density is plotted as a function of the same applied bias at each energy subband of the laser active region. The temperature and density amplitude are rather less pronounced than those of the relaxations time. Analysis of this typical behavior suggests that the most effective laser structure should work under 70 meV bias.

Self-consistent energy balance simulations of hole dynamics in SiGe∕SiTHz quantum cascade structures

“…One approach relies on self-consistent solutions of rate equations. [8][9][10][11][12][13] Another approach uses the microscopic, and computationally more demanding Monte Carlo technique. [14][15][16] Although the latter does not make the assumption of equilibriumlike carrier distributions over states within any single subband, and therefore gives a deeper insight into the electron dynamics, the former are much faster while still giving quite good estimates of device characteristics.…”

Effect of electric field on low temperature multisubband electron mobility in a coupled Ga0.5In0.5P/GaAs quantum well structure

“…[1][2][3] Significant effort also been given utilizing coupled quantum wells or short period superlattices as quantum cascade lasers which have been shown to be reliable, compact, and high power optical sources in the midinfrared and terahertz frequency range. [4][5][6] The application of an electric field, perpendicular to the interface plane, changes the potential profile of a quantum well structure and thereby changes the subband energy levels. The subband wave function distributions also are amended thus affecting electron transport parallel to the interface plane.…”