Figure 4

Photoresponse curves under inter-and sub-bandgap excitations and calculated normalized gain versus intensity. (a) The photoresponse curves under inter-bandgap excitation (λ = 325 nm) at I = 20 W m^-2 in air and vacuum ambiences, (b) the photoresponse curves under sub-bandgap excitation (λ = 808 nm) at increasing I from 408 to 4,080 W m^-2 in air and vacuum ambiences, and (c) the calculated normalized gain versus intensity at λ = 325 and 808 nm in air and vacuum ambiences for the V₂O₅ NW with d = 800 nm and l = 2.5 μm. The insert in (b) shows the photocurrent versus intensity plots at λ = 808 nm in air and vacuum.