Controllable p-n Switching Behaviors of GaAs Nanowires via an Interface Effect

Due to the extraordinary large surface-to-volume ratio, surface effects on semiconductor nanowires have been extensively Investigated In recent years for various technological applications. Here, we present a facile Interface trapping approach to alter electronic transport properties of GaAs nanowires as a function of diameter utilizing the acceptor-like defect states located between the intrinsic nanowire and its amorphous native oxide shell. Using a nanowire field-effect transistor (FET) device structure, p- to n-channel switching behaviors have been achieved with increasing NW diameters. Interestingly, this oxide interface is shown to induce a space-charge layer penetrating deep Into the thin nanowire to deplete all electrons, leading to Inversion and thus p-type conduction as compared to the thick and intrinsically n-type GaAs NWs. More generally, all of these might also be applicable to other nanowire material systems with similar interface trapping effects; therefore, careful device design considerations are required for achieving the optimal nanowire device performances.