title: Scanning photocurrent imaging and electronic band studies in silicon nanowire field effect transistors.
abstract: We report optical scanning measurements on photocurrent in individual Si nanowire field effect transistors (SiNW FETs). We observe increases in the conductance of more than 2 orders of magnitude and a large conductance polarization anisotropy of 0.8, making our SiNW FETs a polarization-sensitive, high-resolution light detector. In addition, scanning images of photocurrent at various biases reveal the local energy-band profile especially near the electrode contacts. The magnitude and polarity of the photocurrent vary depending on the gate bias, a behavior that can be explained using band flattening and a Schottky-barrier-type change. This technique is a powerful tool for studying photosensitive nanoscale devices.
authors.affiliation: The Rowland Institute at Harvard, Cambridge, Massachusetts 02142, USA.
authors.forename: Yeonghwan
authors.initials: Y
authors.lastname: Ahn
authors.forename: James
authors.initials: J
authors.lastname: Dunning
authors.forename: Jiwoong
authors.initials: J
authors.lastname: Park
mesh_terms: D004553:Electric Conductivity; D004559:Electric Wiring; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D019544:Equipment Failure Analysis / Q000379:methods*; D008027:Light; D008422:Materials Testing / Q000379:methods; D018613:Microscopy, Confocal / Q000379:methods*; D049329:Nanostructures / Q000032:analysis* / Q000737:chemistry* / Q000528:radiation effects; D010777:Photochemistry / Q000295:instrumentation / Q000379:methods; D012825:Silicon / Q000032:analysis* / Q000737:chemistry* / Q000528:radiation effects; D014173:Transistors, Electronic
chemical_list: D012825:Silicon