We report the fabrication of Resistor-Capacitor (RC) filters and field effect transistors (FETs) based on pencil drawings on paper, which contain turbostratic graphite crystallites as evidenced from Raman analysis. Pencil drawings have been employed as resistor and an ion gel, 1-butyl-3-methylimidazolium octyl sulfate mixed with polydimethylsiloxane (PDMS) as dielectric, for the fabrication of RC filters with a cut-off frequency of 9 kHz. With ion gel as gate dielectric, an ambipolar electric field effect has been obtained from the pencil-trace at low operating voltages. The carrier mobilities were found to be ∼106 and 59 cm(2) V(-1) s(-1) for holes and electrons, respectively. The mobility value showed only 15% variation among the devices tested, truly remarkable given the simplicity of the fabrication process.

Current generations of 4H-SiC metal-oxide-semiconductor field-effect transistors are still challenged by the high number of defects at the SiO 2 /SiC interface that limit both the performance and gate reliability of these devices. One potential source of the high density of interface defect states (D it) is the stepped morphology on commonly used off-axially grown epitaxial surfaces, favoring incomplete oxidation and the formation of defective transition layers. Here we report measurements on intentionally modified 4H-SiC surfaces exhibiting both atomically flat and stepped regions where the generation of interface defects can be directly linked to differences in surface roughness. By combining spatially resolving structural, chemical, optical, and electrical analysis techniques, a strong increase of D it for stepped surfaces was revealed while regions with an atomically flat SiC surface exhibited close-to-ideal interface properties.

High power SiC MOSFET technologies are critical for energy saving in, e.g., distribution of electrical power. They suffer, however, from low near-interface mobility, the origin of which has not yet been conclusively determined. Here, we present unique concerting evidence for the presence of interface defects in the form of carbon clusters at native thermally processed oxides of SiC. These clusters, with a diameter of 2-5 nm, are HF-etch resistant and possess a mixture of graphitic (sp2) and amorphous (sp3 mixed in sp2) carbon bonds different from the normal sp3 carbon present in 4H-SiC. The nucleation of such defects during thermal oxidation as well as their atomic structure is elucidated by state-of-the-art atomistic and electronic structure calculations. In addition, our property prediction techniques show the impact of the simulated carbon accumulates on the electronic structure at the interface.