
596 Nanosensors: Physical, Chemical, and Biological
the addition of DC voltage tuned the depletion region width. The nanoscale
dimensions of the structure concentrated the electric eld across a small
width, which imparted excellent voltage sensitivity. Within the device, a
transverse electric eld, E
z
, produced a longitudinal strain.
How does the traditional view change at the nanoscale? The traditional view
calls for well-dened, alternating layers of electrodes and piezoelectric
materials. But this view crumbles in nanoscale devices made from semicon-
ductors, where charge depletion smears out the boundary between ...