Synthesis of Al4C3 nanowalls viathermal evaporation and potential application in vacuum microelectronic devices as cold electron emitters

Abstract

Ceramic Al₄C₃ nanowalls were fabricated through a VS mechanism via a chemical vapor deposition (CVD) method. XRD (X-ray diffraction), Raman spectra, SEM (scanning electron micrograph) and TEM (transmission electron micrograph) methods were employed to characterize the product. The synthesized 2-D nanostructures are confirmed to be polycrystalline R-Al₄C₃ with a Al₂O₃ sheath outside the nanosheet. Field emission (FE) measurements show that the turn-on field (where the emission current reaches 10 μA cm⁻²) of the as-prepared sample is 6.0–7.0 V μm⁻¹. According to several comparative experiments, we propose an atmosphere-controlled nanowall growth mechanism from self-assembling templates under a low-pressure environment to explain the growth process.