Laser Patterning a Chem-FET Like Device on a V2O5 Xerogel Film

Vanadium pentoxide xerogel films deposited onto gold microelectrodes were micropatterned by thermally induced conversion into crystalline α-V
₂
O
₅
, using optical lithography written at the focus of a confocal Raman microscope. The laser scribing process improved the electric contact and promoted the n-doping of the film with V
^IV
ions. In this way, a field effect transistor like device was constructed and successfully applied as humidity sensor, where the combined lithographic design and the application of a negative back gate field (V
_G
= -10.0 V) boosted the source-drain current by a hundred times, leading to a large gain in sensitivity.