10.3: Nanodiamond vacuum field emission transistor arrays

A vertically configured nanodiamond vacuum field emission transistor (VFET) is developed. The device is fabricated on a silicon-on-insulator (SOI) substrate, using the active silicon layer patterned with inverted pyramidal mold for nanodiamond deposition and as the self-aligned gate of the final VFET construct. Gate modulation of the emission current is observed with a relatively low gate turn-on voltage. The I_a-V_g-V_a characteristics of the device show distinct linear, saturation and cutoff regions, demonstrating the transistor behaviors. The VFET shows a high dc voltage gain of ~ 1000, an ac voltage gain of ~ 44 and a phase shift of 180° when operated as a voltage amplifier. This nanodiamond VFET promises potential applications in vacuum microelectronics, including integrated circuits.