On the Laser Formation of Suspended Graphene Channels of Photodetectors

The formation of suspended graphene-oxide channels used as photodetectors by femtosecond radiation makes it possible to modify the sensitive channel with high accuracy and without damaging the film. However, the creation of graphene channels is a task that requires new nonstandard solutions. The work considers the photovoltaic effect in a suspended graphene-oxide channel. It is shown that suspended graphene-oxide films formed by femtosecond radiation make it possible to avoid the effect of substrate charges on the suspended conducting graphene channel. Control of the formation of a reduced graphene-oxide channel is studied experimentally. It is found that the structure comprises a graphene-oxide film layer deposited by precipitation from solution on a polydimethylsiloxane substrate with an opening for the suspended part of the film. The samples obtained are examined by scanning electron microscopy and Raman spectroscopy. It is found that, in these microstructures, it is possible to form a specified level of photoresponse depending on the degree of reduction of the structure. The photosensitivity in structures with suspended graphene oxide is determined by transitions of the reduced and unreduced regions of the channel and is 0.8 A/W for a wavelength of 630 nm. The device exhibits high photosensitivity in the visible near-infrared (IR) region.