Topological insulators, such as single-crystal Bi2Se3 nanowires, can be used as the conduction channel in high-performance transistors, a basic circuit building block. Such transistors exhibit current- voltage characteristics superior to semiconductor nanowire transistors, including sharp turn-on, nearly zero cutoff current, very large On/Off current ratio, and well-saturated output current. The metallic electron transport at the surface with good effective mobility can be effectively separated from the conduction of the bulk topological insulator and adjusted by field effect at a small gate voltage. Topological insulators such as Bi2Se3; also have a magneto-electric effect that causes transistor threshold voltage shifts with external magnetic field. These properties are desirable for numerous microelectronic and nanoelectronic circuitry applications, among other applications.