Au Nanoparticle Light Scattering Enhanced Responsivity in Pentacene Phototransistor for Deep-UV Light Detection

In this letter, a pentacene thin-film phototransistor (PTFP) with gold nanoparticles (Au-NPs) decoration in bottom-gate structure was demonstrated. With the Au-NPs, this device is capable of scattering the free-space ultra-violet (UV) irradiation into the pentacene film. Therefore, the PTFP with Au-NPs exhibit 4.5-A/W responsivity with V_GS = 0 V at the wavelength of 240 nm. Meanwhile, an ultimate 32.4-A/W responsivity can be achieved with V_GS = -10 Vat the wavelength of 240 nm. Such an excellent spectral response suggests PTFP is capable for used in daily and disposable UV status assessment.