We investigated the transport properties of a lateral PtSi/n/n(+)-Si Schottky diode prepared on an n-type silicon-on-insulator (SOI) wafer with a special attention on the bipolar transport and the surface effect. With applying a back-gate bias changing from +18 V to -18 V, the unipolar transport behavior switched over to the bipolar one, where an enhanced surface recombination rate due to a high surface-to-volume ratio produced a current density approximately 3 x 10(3) A/cm2 for 2 V bias through a 40 nm-thick and 18 microm-long nanoribbon. The recombination time was estimated to be approximately 1 micros from independent CV measurements, which is much smaller value than that of a bulk. The local Fermi energy level for electrons at the channel center was monitored by an additional voltage probe during each I(D)-V(D) measurement and it revealed the intricate nature of the bipolar transport manifested by the huge asymmetrical hysteretic behavior on a drain bias cycle which is attributed to the charge storage effect and asymmetrical junction profiles.