Large photoresponse of Cu:7,7,8,8-tetracyanoquinodimethane nanowire arrays formed as aligned nanobridges

Abstract

We report large photoresponse in an array of Cu:TCNQ (TCNQ-7,7,8,8-tetracyanoquinodimethane) nanowires fabricated as nanobridge device. The device shows highest photoresponse for excitation wavelength = 405 nm. The current gain at zero bias can reach ∼104 with an illumination power density of 2 × 106 W/m2. The zero bias responsivity is ∼0.3 mA/W, which increases upto 1 A/W for an applied bias of 2.0 V. Dark and illuminated I-V data are analyzed by a model of two Schottky diodes connected back-to-back, which shows that the predominant photocurrent in the device arises from the photoconductive response of the nanowires.