Minority carrier MIS tunnel diodes and their application to electron- and photo-voltaic energy conversion—II. Experiment

The theory of metal-insulator-semiconductor (MIS) tunnel diodes has been described in a companion paper for the case where the insulating layer is so thin that large tunnel currents can flow between the metal and the semiconductor. Of particular interest was the case where the dominant component of tunnel current is between the metal and the minority carrier energy band in the semiconductor (minority carrier diodes). In the present paper, these diodes are investigated experimentally. The differences between minority and majority carrier diodes are demonstrated. Minority carrier diodes are shown to possess properties similar to p-n junction diodes as predicted theoretically. The effectsof different metal contacts, insulator thicknesses, and substrate resistivities are investigated and confirm previous theory. The application of the minority carrier MIS tunnel diodes to energy conversion employing the electron-voltaic effect is investigated experimentally. The diodes were found to be more efficient in this application than p-n junction diodes. Other possible applications of the diodes are as photo-voltaic energy converters, as injecting contacts, and as photo-diodes or elements of photo-diode arrays.