Effect of oxygen vacancy concentration on indium tungsten oxide UV-A photodetector.

An indium tungsten oxide (IWO) ultraviolet (UV) photodetector was fabricated with radio frequency magnetron sputtering. IWO thin films were deposited on devices under various oxygen partial pressure ambiences. With higher oxygen flow ratio, the oxygen vacancies were filled up, reducing the carrier concentration. Lowering the number of defects, such as oxygen vacancies, was effective for optimizing device performance. The on-off current ratio of an IWO UV-A photodetector at 10% oxygen partial pressure could reach 4.56 × 10 4 , with a photoresponsivity of 1.9 × 10 -2 A W -1 , as well as a rejection ratio of 2.68 × 10 4 at a voltage bias of 10 V.