Functionalized graphene/silicon chemi-diode H₂ sensor with tunable sensitivity.

A reverse bias tunable Pd- and Pt-functionalized graphene/Si heterostructure Schottky diode H2 sensor has been demonstrated. Compared to the graphene chemiresistor sensor, the chemi-diode sensor offers more than one order of magnitude higher sensitivity as the molecular adsorption induced Schottky barrier height change causes the heterojunction current to vary exponentially in reverse bias. The reverse bias operation also enables low power consumption, as well as modulation of the atomically thin graphene's Fermi level, leading to tunable sensitivity and detection of H₂ down to the sub-ppm range.

Tunable reverse-biased graphene/silicon heterojunction Schottky diode sensor.

A new chemical sensor based on reverse-biased graphene/Si heterojunction diode has been developed that exhibits extremely high bias-dependent molecular detection sensitivity and low operating power. The device takes advantage of graphene's atomically thin nature, which enables molecular adsorption on its surface to directly alter graphene/Si interface barrier height, thus affecting the junction current exponentially when operated in reverse bias and resulting in ultrahigh sensitivity. By operating the device in reverse bias, the work function of graphene, and hence the barrier height at the graphene/Si heterointerface, can be controlled by the bias magnitude, leading to a wide tunability of the molecular detection sensitivity.

Clustering effects on discontinuous gold film NanoCells.

Reproducible negative differential resistance (NDR)-like switching behavior is observed in NanoCells. This behavior is attributed to the formation of filaments and clusters between the discontinuous gold films. Control experiments are performed by self-assembly of insulating molecules between the gold islands and conducting molecules on these islands.

Micro/nanoscale mechanical and tribological characterization of SiC for orthopedic applications.

Micro/nanomechanical and tribological characterization of SiC has been carried out. For comparison, measurements on SiC, CoCrMo, Ti-6Al-4V, and stainless steel have also been made. Hardness and elastic modulus of these materials were measured by nanoindentation using a nanoindenter.