Influence of magnesium doping on carbon dots for enhancing photocurrent generation in photodetectors

Abstract In recent years, carbon dots (CDs) doped with metals have garnered significant attention. Metal doping introduces free electrons, thereby increasing the carrier concentration within the CDs and altering their intrinsic properties. This study explores the influence of magnesium (Mg) doping on CDs (MCDs) to enhance photocurrent generation in photodetectors (PDs). CDs and MCDs are synthesised using a microwave method. Comparative analysis of the structural and optical properties of MCDs and CDs reveals the impact of Mg doping on the surface of CDs. Characterization techniques demonstrate that Mg doping enhances conjugation within the CDs, leading to improved charge transfer by reducing bandgap and improving the density of states. Photocurrent measurements are conducted under visible, long UV, and short UV illumination. The results indicate an increase in photocurrent, particularly under 365 nm illumination, rising from 3.86 × 10 −6 A to 2.98 × 10 −5 A, suggesting a positive correlation between Mg concentration and enhanced photocurrent.