Nanomachining of mesoscopic electronic devices using an atomic force microscope

An atomic force microscope (AFM) is used to locally deplete the two-dimensi onal electron gas (2DEG) of a GaAs/AlGaAs heterostructure. The depletion is induced by repeated mechanical scribing of the surface layers of the heter ostructure using the AFM tip. Measuring the room-temperature resistance acr oss the scribed lines during fabrication provides in situ control of the de pletion of the 2DEG. Variation of the room-temperature resistance of such l ines tunes their low-temperature characteristics from tunneling up to insul ating behavior. Using this technique, an in-plane-gate transistor and a sin gle-electron transistor were fabricated. (C) 1999 American Institute of Phy sics. [S0003-6951(99)00234-X].