High carrier mobility in single ultrathin colloidal lead selenide nanowire field effect transistors.

Ultrathin colloidal lead selenide (PbSe) nanowires with continuous charge transport channels and tunable bandgap provide potential building blocks for solar cells and photodetectors. Here, we demonstrate a room-temperature hole mobility as high as 490 cm(2)/(V s) in field effect transistors incorporating single colloidal PbSe nanowires with diameters of 6-15 nm, coated with ammonium thiocyanate and a thin SiO(2) layer. A long carrier diffusion length of 4.5 μm is obtained from scanning photocurrent microscopy (SPCM). The mobility is increased further at lower temperature, reaching 740 cm(2)/(V s) at 139 K.