Reduced graphene oxide/carbon black thin-film mid-infrared photodetector

Abstract

Reduced graphene oxide (RGO) films are promising materials for room temperature infrared photodetector due to their unique electronic band structure, excellent electrical and optical properties. However, the surface of RGO films often exhibits a metallic luster and poor light absorption efficiency, which severely limits the detector performance. Here, in response to these defects, a uniform layer of carbon black (CB) was deposited onto the RGO films to make RGO/CB composite film using a convenient flame method. The infrared thermography revealed that the CB layer could absorb more incident light under the same conditions and convert to heat for RGO thermoelectric effect. Under the 4 μm mid-infrared (MIR) laser irradiation, the photocurrent of the suspended RGO/CB photodetector exhibited a significant enhancement, and the optimum detectivity was 2.5 times higher than that of the pure RGO films detector, reaching 8.4×10⁷ cm·Hz^1/2·W^-1 . This simple method by introducing the CB layer to improve the light absorption provides a new way for effective MIR detection at the room temperature.