Persistent Photoconductivity in Monolayer MoS$_{2}$ on Organic-molecule-functionalized Substrates

We demonstrate a giant persistent photoconductivity (PPC) effect in monolayer MoS$_{2}$ in which the photocurrent robustly persists after illumination has ceased. This PPC effect in monolayer MoS$_{2}$ on organic-molecule-functionalized substrates sustains up to room temperature and can be highly suppressed by applying source--drain/back-gate voltages to the transistors. Based on this persistency and controllability of the PPC effect, we achieve a room-temperature conductance bistability by utilizing optical and electrical pulses. The observed giant PPC effect in MoS$_{2}$ can be attributed to a large electron-capture barrier of trap states, which is estimated to be as high as 390 meV.