Fig. 1
From: All-silicon photovoltaic detectors with deep ultraviolet selectivity
Characterizations of Si3N4 film. a AFM image of the Si3N4 film, the root mean square (RMS) of roughness is only 0.76 nm, showing an ultra-smooth surface. b Cross-sectional SEM morphology of the Si3N4 film. The thickness is around 50 nm. c HRTEM image of the Si3N4/Si interface. d-e Elements mapping of nitrogen and silicon. f The EDS spectrum of Si3N4. 10 nm platinum is sputtered on the Si3N4 film surface to improve conductivity in EDS characterization. g-h XPS pattern of the Si3N4 film, the characteristic peaks of N1s and Si2p are detected. The black dots represent experimental data. i Transmission spectrum of Si3N4 film, and this Si3N4 film is deposited on sapphire substrates by ICPCVD. The transmittance remains over 50% at 220 nm. The fluctuation of the spectrum in the visible band comes from the light interference. j FTIR spectroscopy of Si3N4 film; the peak of Si-N bond is found around 837 cm− 1