The double Gaussian distribution of barrier heights in Au/n-GaAs Schottky diodes from I-V-T characteristics

The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of Au/n-GaAs contacts have been measured in the temperature range of 80-300 K. An abnormal decrease in the experimental BH Phi(b) and an increase in the ideality factor n with a decrease in temperature have been observed. This behaviour has been attributed to the barrier inhomogeneities by assuming a Gaussian distribution of barrier heights at the metal-semiconductor interface. The ternperature-dependent I-V characteristics of the Au/n-GaAs contact have shown a double Gaussian distribution giving mean barrier heights of 0.967 and 0.710 eV and standard deviations of 0.105 and 0.071 V, respectively. A modified In(I-0/T-2) - q(2)sigma(2)(s)/2k(2)T(2) versus I/T plot for the two temperature regions then gives Phi(b0) and A* as 0.976 and 0.703 eV, and 13.376 and 8.110 A cm(-2) K respectively. Furthermore, a value of -0.674 meV K-1 for the temperature coefficient has been obtained, and the value of -0.674 meV K-1 for the Au/n-GaAs Schottky diode is in close agreement with those in the literature.