Preparation Mechanism of Silicon Carbide Quantum Dots by Chemical Etching Method and Its Monodispersity Regulation

KANG Jie; WANG Xiaoyan; LI Lianrong; SUN Weiyun; PAN Quanxi

doi:10.19329/j.cnki.1673-2928.2026.02.008

Abstract：To address the challenges in regulating the particle size and optical properties of indirect bandgap semiconductor quantum dots,this study develops an efficient preparation process for silicon carbide(SiC)quantum dots(QDs)so as to realize their precise size control and monodispersity optimization.β-SiC powder synthesized via self-propagating high-temperature synthesis(SHS)was used as the raw material,and an efficient etching was conducted with a HF-HNO₃ binary mixed acid etching system.Based on the density gradient centrifugation theory,the monodispersity of QDs was regulated through a high-gravity chromatography trimming process.Electron microscopy and fluorescence spectrophotometry were employed to systematically characterize the micromorphology and optical properties of the products,and the etching reaction mechanism and the laws of the trimming process were further investigated.The synergistic effect of HNO₃ oxidizing the raw SiC powder to form SiO₂ and HF cleaving the Si-O bonds enabled the rapid preparation of SiC QDs with an average diameter of 4.9 nm.The uneven particle size distribution after ultrasonication resulted in a slight red shift of the emission peak with the increase of excitation wavelength.By adjusting the high-gravity coefficient(μ=3000,4000,5000),the precise regulation of SiC QD sizes in the range of 4.6～7.1 nm was achieved,and a correlation mechanism among"high-gravity coefficient–particle size–spectral properties"was preliminarily established.The novel preparation and regulation process for SiC QDs proposed in this study provides a new technical pathway for the regulation of particle size and optical properties of indirect bandgap semiconductor quantum dots,and exhibits significant theoretical and application value.