We present results from a numerical study on heating in Hg0.72Cd0.28Te induced by 4.2 μm laser pulses in the μs regime. A number of highly nonlinear mechanisms contribute to the heating process, their relative importance being dependent on the instantaneous irradiance and the material temperature. The mechanisms include one- and two-photon absorption across the band gap, inter-valence band absorption between the light- and heavy hole bands, electron-hole recombination, free-carrier absorption, hot-carrier generation, and refractive index changes. A special feature of this material is the fact that the direct band gap increases with temperature. This eventually terminates one-photon absorption processes from the valence to the conduction band. The varying band gap also introduces changes in the electron- and light hole masses and thereby in the separation between the light- and heavy hole bands, thus strongly affecting inter-valence band absorption. Therefore first principles electronic structure calculations were used to determine the band structure and the inter-valence band absorption. The simulations also show that hot carrier effects can have a significant influence on the amount of energy the material can absorb.
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