Quantum statistics of an electron–hole plasma

Thermodynamic functions of an electron–hole plasma in an optically excited semiconductor are derived in the nondegenerate region. The existence of excitons and the ionization equilibrium are discussed in the n e – T (electron density–temperature) plane. Above the Mott curve ( r 0 = 0.84 a 0 , r 0 screening length, a 0 Bohr's radius) excitons do not exist. Besides the well known electron–hole droplet phase transition the critical point of which lies above the Mott curve, a region of instability is found below the Mott curve which might correspond to a plasma phase transition (weakly ionized plasma → strongly ionized plasma). Outside of this instability region at the Mott curve a diffuse phase transition (Mott‐transition) exists.