Luminescence from Electron–Hole Drops in Undoped GaP

The radiative recombination from electron–hole drops (EHD) is investigated in highly excited pure GaP in the temperature range of T = 2 to 77 K. The fundamental parameters of the electronhole condensate are obtained by comparison of the experimental and calculated lineshape of the luminescence band, taking into account the “camel's back” density of states of the lower conduction band near the X‐point. The influence of the real density of states of the lower conduction band near the X‐point. The influence of the real density of states on the lineshape is discussed. The equilibrium carrier density and the work function are determined to be neq = 7.4 × 1018 cm−3 and Φexp 15.5 meV, respectively. The “camel's back” depth is estimated to be δ = (9.1 × 1) meV. It appears that the critical temperature of the EHD is Tc ≧ 70 K. Decay measurements led to the conclusion that the luminescence in the high energy tail of the band is caused by a radiative recombination from a gas‐like plasma.