Electric-field behavior and charge-density distribution in semi-insulating gallium arsenide Schottky diodes

The behavior of the electric field and the charge-density distribution in semi-insulating gallium arsenide Schottky diodes have been analyzed by optical-beam-induced current and surface potential measurements. The electric field exhibits three different regions across the detector, the characteristics of which depend on the reverse applied voltage. Furthermore, a positive box-shaped space charge region exists, separated from the Schottky barrier by a neutral space-charge region, and widens and moves towards the Ohmic contact at increasing the reverse bias voltage. This study adds substantial information to the knowledge of the space-charge distribution in semi-insulating Schottky diodes, discriminates between the existing models on the electric field, and provides essential information to understand nuclear detector performance.