Persistent Current Reduction in Metal-Semiconductor FETs With a ZnCoO Channel in an External Magnetic Field

Transparent metal-semiconductor field-effect transistors (MESFETs) with a ZnCoO channel have been fabricated by pulsed laser deposition on c-plane sapphire substrates at a temperature of 550°C. The paramagnetic properties have been confirmed by magnetotransport measurements on undepleted ZnCoO films without Schottky gate contacts. The Au/AgxO Schottky gate contacts were processed by optical lithography and metallization. Below 50 K, the MESFET characteristics are persistently changed from a low resistance state (LRS) to high resistance state by an external magnetic field. The MESFET can be switched back into the LRS only by heating it up to room temperature.