INFRARED RADIATION DETECTOR WITH YBA2CU3OX THIN-FILM

We investigated an infrared (IR) radiation detector using a c-axis ori ented YBa2Cu3Ox thin film with a microbridge structure. The photorespo nse was measured under IR radiation and was found to depend on the bia s current. A bolometric response was observed under relatively low bia s current, which was inversely proportional to the square root of the modulation frequency of IR irradiation. The frequency dependence fan b e explained by a heat diffusion process that is similar to that of a m icrobolometer. With increasing bias current, a nonbolometric response was observed just above the superconducting transition temperature (T- c). This was caused by the enhancement of additional flux creep induce d by modulated IR light. which was equivalent to an increase in resist ance. The maximum responsivity and noise equivalent power (NEP) were 1 .7 x 10(4) V/W and 2.1 x 10(-14) W/Hz(1/2), respectively.