Vertical versus lateral GaN Schottky ultraviolet detectors and their gain mechanism

摘要

We have implemented Schottky barrier GaN ultraviolet detectors, both in vertical and in lateral configuration. The devices exhibit a high gain at both reverse and forward bias. The gain mechanism is attributed to trapping of minority carriers at the semiconductor-metal interface, with excellent agreement between the calculated responsivity and the experiment. However, the vertical detector zero-bias responsivity (without gain) is two orders of magnitude higher. This is attributed to improved ohmic back contacts, due to the highly doped buried layer.