The electronic structure of SiC/SiO₂ interfaces was studied for different SiC polytypes (3C, 4H, 6H, 15R) using internal photoemission of electrons from the semiconductor into the oxide. The top of the SiC valence band is located 6 eV below the oxide conduction band edge in all the investigated polytypes, while the conduction band offset at the interface depends on the band gap of the particular SiC polytype. In the energy range up to 1.5 eV above the top of the SiC valence band, interface states were found. Their electron spectrum is similar to that of sp²‐bonded carbon clusters in diamond‐like a‐C:H films suggesting the presence of elemental carbon at the SiC/SiO₂ interfaces.

Low-temperature electrical measurements and photon-stimulated electron tunneling experiments reveal the presence of a high density of interface states at around 0.1 eV below the conduction band of 4H–SiC at its interface with thermally grown ${\mathrm{SiO}}_{\mathrm{2}}.$ These states, related to defects in the near-interfacial oxide layer, trap a considerable density of electrons from the SiC, and are likely responsible for the severe degradation of the electron mobility observed in the surface channel of ${\mathrm{4H–SiC/SiO}}_{\mathrm{2}}$ devices. The negative impact of the observed defects can be minimized by using SiC modifications (e.g., 6H, 15R, 3C) with a larger conduction band offset with the oxide than 4H–SiC leading to a largely reduced density of electrons trapped in the oxide.

The preoxidation cleaning of silicon carbide surfaces (3C, 4H, 6H polytypes) by exposing them to ultraviolet radiation and oxygen is shown to produce a significant improvement in the electronic properties of SiC/SiO₂ interfaces. It is found that this treatment results in a removal of defect species, otherwise present at the SiC surface after thermal oxidation of SiC. Carbon clusters are proposed as the attacked species responsible for a substantial part of the SiC/SiO₂ interface states.

A chip-size spectrometer is realized by combining a linear variable band-pass filter with a CMOS camera. The filter converts the spectral information of the incident light into a spatially dependent signal that is analyzed by the camera. A fluidic platform is integrated onto the spectrometer for analyzing the fluorescence from moving objects. The target is continuously excited within an anti-resonant waveguide, and its fluorescence spectrum is recorded as the object traverses the detection area.