Scanning photocurrent imaging and electronic band studies in silicon nanowire field effect transistors.
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.
Ahn
Yeonghwan
Y
The Rowland Institute at Harvard, Cambridge, Massachusetts 02142, USA.
Dunning
James
J
Park
Jiwoong
J
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
D012825:Silicon