Electron–Hole Plasma Expansion in Direct‐Gap GaAs1−xPx

The e‐h plasma in the ternary alloy GaAs 1− x P 2 below direct‐indirect crossover is studied at 2 K by means of very high excitation photoluminescence measurements. The most interesting feature observed is an extremely efficient expansion of the excited region when the particle density reaches the value n* needed to minimize the free energy. This behaviour and the corresponding spectral evolution with power density are accounted for by a model where pressure‐induced flow of particles away from the pumped region becomes competitive with recombination mechanisms.