Tunable Interfacial Properties of CdS/CdSe Nanoheterostructures: Experimental and Theoretical Exploration

This study explores the Field Emission (FE) properties of chemically synthesized CdSe Nanoparticles (NP), CdS Nanosheets (NS), and CdS/CdSe Nanoheterostructures (NHS). The formation of the CdS/CdSe NHS induces band alignment which reduces the effective surface potential barrier, and enhances local electric field concentration at the interface. These effects facilitate efficient electron tunneling by lowering the work function and improving charge transport across the junction. Density Functional Theory (DFT) confirms the reduced work function improves FE behaviour, attributed to bandgap reduction, stronger orbital overlap, and efficient interfacial charge transfer collectively contributing to reduced electron emission barriers. As a result, the CdS/CdSe NHS exhibits significantly enhanced FE performance, with a 31% lower turn-on field (3.2 V/µm) than CdSe NP and 22% lower than CdS NS, while achieving a ∼80 times higher emission current density at 4.4 V/µm. Enhanced emission efficiency arises from increased electron emission sites and enhanced local electric fields. Furthermore, the NHS exhibits excellent charge-discharge cycling performance, indicating promising potential for energy storage applications. For the first time, CdS/CdSe NHS is reported as a highly promising material for next-generation FE devices. These results establish as a powerful strategy for multifunctional nanomaterials for advanced technological applications.