Abstract
We investigated the metal-semiconductor charge injection process to find the most suitable ohmic metal for Orange-Dye (OD) as organic semiconductor. For this purpose, different metal-semiconductor Schottky diodes such as (a) Au/OD/Al, (b) SnO2/OD/Al, (c) Ni/OD/Al, and (d) Ga/OD/Al were fabricated and electrically characterized. It is observed that all Schottky diodes follow space charge limited model to define their charge transport mechanism and at the same time Ga/OD interface offered best electrical response, while Ni/OD interface offered lowest electrical responses. As, aluminum electrode and all other fabrication parameters are same for all Schottky diodes, therefore it is inferred that the improved electrical response for Ga/OD/Al Schottky is mainly due to Ga-OD interface. To compare, a simple relative charge injection-efficiency parameter (with respect to Ga) is calculated as 70, 32, 30 and 100% for Au, SnO2, Ni, and Ga anode respectively. It is further observed that relative charge injection efficiency parameter is not a strong function of higher electric-field.