Comparative study of different metals for Schottky barrier diamond betavoltaic power converter by EBIC technique

In order to improve the performance of betavoltaic converters based on synthetic IIb diamond Schottky structure, we performed comparative studies of converters with Al, Hf, Pt, and Au metals forming the Schottky barrier by means of the electron beam‐induced current (EBIC) method. Nearly full collection of generated electron–hole pairs was found for all fabricated structures. The aluminum contact showed the lowest energy loses due to negligible electrons absorption and backscattering. But the conversion efficiency of the Al‐contact Schottky diode was just about 2% because of its low open‐circuit voltage. We attributed the reduction of the Schottky barrier height to local defects observed by EBIC. The diamond cells with platinum contact showed the best performance of about 6% with a relatively high open‐circuit voltage >1 V and a good incident beam multiplication factor. Thereby platinum forms the most stable and effective Schottky barrier contact for diamond betavoltaic cells.