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By using arrays of nanowires with intentionally broken symmetry, we were able to detect microwaves up to 110 GHz at room temperature. This is, to the best of our knowledge, the highest speed that has been demonstrated in different types of novel electronic nanostructures to date. Our experiments showed a rather stable detection sensitivity over a broad(More)
One of the most important physical parameters to describe the quality of a piece of semiconductor material is the electron scattering length le. Also referred to as the mean-free path, it stands for the average distance between the randomly distributed scatterers in the material, such as lattice defects, impurities, and phonons. The electron mean-free path(More)
The THz spectrum lies between microwaves and the mid-infrared, a region that remains largely unexplored mainly due to the bottleneck issue of lacking compact, solid state, emitters and detectors. Here, we report on a novel asymmetric-nanochannel device, known as the self-switching device, which can operate at frequencies up to 2.5 THz for temperature up to(More)
A ballistic-electron transport-based semiconductor nanorectifier, also known as a ballistic rectifier, has been demonstrated to have an intrinsic zero threshold voltage. In this paper, we characterize its low-frequency noise properties and show that the zero-threshold property enables elimination of the flicker noise. As a potential terahertz detector, the(More)
An approach has been developed to use atomic-force microscope (AFM) to pattern materials at the nanoscale in a controlled manner. By introducing a thermal-annealing process above the glass-transition temperature of poly (methylmethacrylate) (PMMA), the profile of indented nanopatterns has been dramatically improved by abatement of the tip-induced debris.(More)
Mechanically flexible mobile phones have been long anticipated due to the rapid development of thin-film electronics in the last couple of decades. However, to date, no such phone has been developed, largely due to a lack of flexible electronic components that are fast enough for the required wireless communications, in particular the speed-demanding(More)
Polycrystalline zinc oxide (ZnO) thin-film transistors with a Ta<sub>2</sub>O<sub>5</sub> high- k gate dielectric layer are fabricated by radio-frequency magnetron sputtering at room temperature. Under the optimal deposition conditions, the devices show saturation mobility values over 50 cm<sup>2</sup>/Vs, an ON/OFF ratio of , and a subthreshold voltage(More)
Although graphene has the longest mean free path of carriers of any known electronic material, very few novel devices have been reported to harness this extraordinary property. Here we demonstrate a ballistic nano-rectifier fabricated by creating an asymmetric cross-junction in single-layer graphene sandwiched between boron nitride flakes. A mobility(More)
Terahertz (THz) technology has attracted rapidly increasing attention due to a very broad range of potential applications, e.g., medical imaging and homeland security. Perhaps more importantly, developing electronic devices capable of operating at THz frequencies will have great impact on future generation computation and communication. Despite enormous(More)
Low operating voltages have been long desired for thin-film transistors (TFTs). However, it is still challenging to realise 1-V operation by using conventional dielectrics due to their low gate capacitances and low breakdown voltages. Recently, electric double layers (EDLs) have been regarded as a promising candidate for low-power electronics due to their(More)