EVIDENCE FOR NON-EQUILIBRIUM FREE ELECTRON DENSITY IN A1GaAs AT LOW TEMPERATURES

Due to the strong temperature dependence of the capture rate, the DX centre in AlGaAs is expected to show non-equilibrium occupancy at low temperatures. Results of Thermally Stimulated Capacitance and Capacitance-Voltage measurements, carried out at 77 K on Au-Al(x)Ga1-xAs (x = 0.25) Schottky barriers, are strongly influenced by the cooling rate. This demonstrate that in practical experiments the free electron density commonly observed at low temperature is far from thermodynamical equilibrium