Tailoring the electrical properties of tellurium nanowires via surface charge transfer doping

We presented an attempt to modulate the electrical property of tellurium nanowires (TeNWs) via a surface charge transfer doping method. The TeNWs with length of several tens of micrometers and diameters of 20–50 nm were prepared by a simple hydrothermal method at 160 °C for 20 h. High-resolution transmission electron microscope image combined with selected area electron diffraction pattern shows the single-crystal nature and a growth direction along [001]. Electrical analysis of the individual TeNW-based field effect transistor before and after surface coating reveals that MoO3 and CuPc thin layer coating can greatly enhance both electrical conductivities and hole concentrations. Such a surface hole injection effect, according to the band energy alignment, can be attributed to the huge differences in work functions between TeNW and MoO3/CuPc. Furthermore, the influence of the deposited layer on carrier mobility is strikingly different, which is believed to be due to the discrepancy in surface scattering upon surface coating. The results from this study provide an effective alternative for doping other semiconductor nanostructures.