PHYSICAL PROPERTIES OF TIJJ POTENTIAL BARRIER OF Pt/n-GaAs SCHOTTKY MIXER DIODES

The temperature dependence of the current-voltage characteristic of Pt/n-GaAs Schottky diodes which are used as mixers in low noise THz heterodyne receivers is investigated. Two different groups of diodes are identified. While the barrier height and temperature dependence of the di-odes of one group are determined by the energy gaps of GaAs they are determined by defects at the metal-semiconductor interface for the diodes of the other group. For a defect free interface the barrier height has no influence on the noise performance of the diode. The influence of spa-tial inhomogeneities at the interface on the noise temperature is investigated. It was found that the noise temperature increases with increasing magnitude of the spatial inhomogeneities. 1