Controlled Growth of Heterostructured Ga/GaAs Nanowires with Sharp Schottky Barrier

Because of the inevitable Fermi level pinning on surface/interface states of nanowires, achieving high-performance nanowire devices with controllable nanoscale contacts is always challenging but important. Herein, single-crystalline heterostructured Ga/GaAs nanowires with sharp hetero-Schottky interfaces have been successfully synthesized on amorphous substrates by utilizing Au nanoparticles as catalytic seeds via chemical vapor deposition. These nanowires are found to grow with the hemispherical Au₇Ga₂ catalytic tips following the vapor-liquid-solid mechanism. During the growth, simply by manipulating the source and growth temperatures, the Ga precipitation rate from Au-Ga alloy tips as well as the reaction rate of Ga precipitates with As can be reliably controlled in order to tailor the length (0-170 nm) of Ga nanowire segments obtained in the heterostructure. When configured into field-effect transistors, these Ga/GaAs NWs exhibit the p-type conductivity with a sharp hetero-Schottky barrier of ∼1.0 eV at the atomically connected Ga segment/GaAs NW body interface, in which this barrier height is close to the theoretical difference between the GaAs Fermi level (5.1-5.3 eV) and the Ga work function (∼4.3 eV), suggesting the effective formation of nanoscale contact by minimizing the Fermi level pinning, being advantageous for advanced nanoelectronics.