Pentacene-Based Photodetector in Visible Region With Vertical Field-Effect Transistor Configuration

TLDR: In this paper, the VFET-based photo-detector with ITO/Pentacene(80 nm)/Al(15 nm) configuration was investigated in full visible region.

Abstract: Electrical and detection performances of pentacene-based photodetector with vertical field-effect transistor (VFET) configuration were investigated in full visible region. By comparing with planar FET-based photodetector ITO/ PMMA(520 nm)/Pentacene(35 nm)/Au, the VFET-based photo-detector ITO/Pentacene(80 nm)/Al(15 nm)/Pentacene(80 nm)/ Au exhibits better performance. At an output current of ca. $-8\times 10^{-7}$ A, the threshold voltage ( $V_{\rm th}$ ) was −0.61 V for the VFET-based device at $V_{\mathrm {DS}} = -2$ V, but $V_{\mathrm {th}} = -7.1$ V for the planar one at $V_{\mathrm {DS}} = -12$ V. The performance of photodetectors depends on incident monochromatic light, and the VFET-based photodetector showed a maximum responsivity of 188 mA/W and a photosensitivity peak of 588 under 350-nm light, which were $\sim 11.75$ and 2.83 times as that of the planar one, respectively. Therefore, it provides an easy way to get the VFET-based organic photodetectors in full visible region with excellent photosensitivity, responsivity, and light selectivity, showing its promising application in all-organic image sensors working at low voltages.