High-speed visible-blind GaN-based indium-tin-oxide Schottky photodiodes

We have fabricated GaN-based high-speed ultraviolet Schottky photodiodes us ing indium-tin-oxide (ITO) Schottky contacts. Before device fabrication, th e optical transparency of thin ITO films in the visible-blind spectrum was characterized via transmission and reflection measurements. The devices wer e fabricated on n-/n+ GaN epitaxial layers using a microwave compatible fab rication process. Our ITO Schottky photodiode samples exhibited a maximum q uantum efficiency of 47% around 325 nm. Time-based pulse-response measureme nts were done at 359 nm. The fabricated devices exhibited a rise time of 13 ps and a pulse width of 60 ps. (C) 2001 American Institute of Physics.