Here we show that gas-phase doping by means of NH3 plasma exposure is a highly flexible and manufacturable process for graphene electronics. The nitrogen-containing radicals can readily form covalent bonds with the carbon lattice and keep stable in the postannealing for damage restoration. The amount of charge transfer can be fine tuned by controlling the exposure time and monitored by the systematic shift in the Raman G mode and the Gds−Vg curves in transport measurements. The maximum doping level can reach 1.5×1013 cm−2.

We describe a technique for fabricating ultrashort-channel carbon nanotube field-effect transistors, using individual V2O5 nanowires as evaporation masks to define the conduction channel. The flexible and neat nanowires can be readily oriented to cross over the underlying nanotubes and produce a uniform nanogap of ∼10nm. The transport through such ultrashort nanotube devices shows a significant increase of subthreshold slope and leakage current in the off state, both of which are not observed in long-channel regime. These effects become more pronounced as the channel length is further shrunk and set fundamental constraints in transistor function of the current architecture.

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We demonstrate a Si/SiO/SiO2-based period-chirped guided mode resonance (GMR) filter to discriminate telecom o-band wavelengths by spatially resolved horizontal movement. Continuously period-chirped silicon gratings were fabricated by using a Lloyd’s laser interferometer with a convex mirror. Due to the large waveguide effective index, the GMR filter can be realized with a short grating period, thus enabling a slow grating period transition along the sample position and high optical resolution in wavelength discrimination. Depositing a SiO/SiO2 stack on top of silicon gratings enables a narrowband GMR filter with a linewidth of 1–1.5 nm over a wavelength range of 1260–1360 nm. By using the chirped GMR filter as a dispersive device, the optical spectra of a near-infrared broadband light source are reconstructed. An optimized aspheric mirror is proposed to further improve the linearity of chirped gratings. Such a period-chirped GMR filter is promising for compact on-chip spectroscopy and sensing applications.