Electrical spin injection and detection in Si nanowires*

While electrical spin injection and detection in bulk Si has now been established, the availability of high quality single crystalline silicon nanowires has stimulated considerable interest in demonstrating spin-polarized transport in these 1-dimensional structures. Here, we report our efforts to electrically inject spin-polarized electrons from cobalt contacts into n-type silicon nanowires through Al$_{2}$O$_{3}$ tunnel barriers. The electrically doped nanowires were synthesized by the vapor-liquid-solid process with a cold wall chemical vapor deposition system using silane and phosphine precursors. Low temperature magneto-transport studies have shown spin-valve like behavior in both two-terminal and four-terminal lateral devices. The spin-valve signal as functions of temperature and bias voltage will be discussed. We will also show the influence of defects and trap states on the stability of nanowire devices.