11 research outputs found
Atomic White-Out: Enabling Atomic Circuitry Through Mechanically Induced Bonding of Single Hydrogen Atoms to a Silicon Surface
We report the mechanically induced formation of a silicon-hydrogen covalent
bond and its application in engineering nanoelectronic devices. We show that
using the tip of a non-contact atomic force microscope (NC-AFM), a single
hydrogen atom could be vertically manipulated. When applying a localized
electronic excitation, a single hydrogen atom is desorbed from the hydrogen
passivated surface and can be transferred to the tip apex as evidenced from a
unique signature in frequency shift curves. In the absence of tunnel electrons
and electric field in the scanning probe microscope junction at 0 V, the
hydrogen atom at the tip apex is brought very close to a silicon dangling bond,
inducing the mechanical formation of a silicon-hydrogen covalent bond and the
passivation of the dangling bond. The functionalized tip was used to
characterize silicon dangling bonds on the hydrogen-silicon surface, was shown
to enhance the scanning tunneling microscope (STM) contrast, and allowed NC-AFM
imaging with atomic and chemical bond contrasts. Through examples, we show the
importance of this atomic scale mechanical manipulation technique in the
engineering of the emerging technology of on-surface dangling bond based
nanoelectronic devices.Comment: 9 pages (including references and Supplementary Section), 8 figures
(5 in the main text, 3 in Supplementary
New fabrication technique for highly sensitive qPlus sensor with well-defined spring constant
A new technique for the fabrication of highly sensitive qPlus sensor for
atomic force microscopy (AFM) is described. Focused ion beam was used to cut
then weld onto a bare quartz tuning fork a sharp micro-tip from an
electrochemically etched tungsten wire. The resulting qPlus sensor exhibits
high resonance frequency and quality factor allowing increased force gradient
sensitivity. Its spring constant can be determined precisely which allows
accurate quantitative AFM measurements. The sensor is shown to be very stable
and could undergo usual UHV tip cleaning including e-beam and field evaporation
as well as in-situ STM tip treatment. Preliminary results with STM and AFM
atomic resolution imaging at of the silicon
surface are presented.Comment: 5 pages, 3 figure
Binary Atomic Silicon Logic
It has long been anticipated that the ultimate in miniature circuitry will be
crafted of single atoms. Despite many advances made in scanned probe microscopy
studies of molecules and atoms on surfaces, challenges with patterning and
limited thermal stability have remained. Here we make progress toward those
challenges and demonstrate rudimentary circuit elements through the patterning
of dangling bonds on a hydrogen terminated silicon surface. Dangling bonds
sequester electrons both spatially and energetically in the bulk band gap,
circumventing short circuiting by the substrate. We deploy paired dangling
bonds occupied by one movable electron to form a binary electronic building
block. Inspired by earlier quantum dot-based approaches, binary information is
encoded in the electron position allowing demonstration of a binary wire and an
OR gate