Heating and evaporation of a two-dimensional electron-hole liquid by heat pulses

The dynamics of low-temperature ($T=5$ K) photoluminescence spectra of Si/Si$_{1-x}$Ge$_x$/Si heterostructures ($x=0.045$) under the influence of a stream of nonequilibrium phonons (heat pulses) propagating in the structure is investigated. The rapid evaporation of the electron-hole liquid in the quantum well of the structure is observed as the liquid is heated by nonequilibrium phonons. It is established that an increase in the exciton-gas density in the quantum well is caused by the evaporation of the electron-hole liquid and by an increase in the rate of exciton capture by the quantum well. It is shown that the interaction with nonequilibrium phonons results in the dissociation of bound-exciton complexes in the Si layers, which is accompanied by an increase in the exciton concentration and lifetime.