The realization of the nanoscale bar-codes based on CdS branched nanostructure

Abstract

The nanostructures with controllable emission colors have shown great attention for achieving high throughput sensing, anti-counterfeiting, and information security. Here, a branched CdS nanostructure with Sn nanoparticles implanted in the junctions is proposed to construct lateral photonic barcodes in a two dimensional domain. Due to the encapsulated Sn nanoparticles, the plasmon enhanced photoluminescence is practically observed. However, with the generation of the high-energy electrons under illumination of the electron beam, the transfer process occurring between the CdS and Sn nanoparticles, result in cathodoluminescence quenching at the junctions. In addition, both temperature coefficients and Debye temperatures of the CdS branched nanostructures are determined to be 5.56 × 10−4 eV/K and 97 K, respectively, based on the temperature dependent photoluminescence spectrum. Also, the emission intensity of the band edge and the defect related emission can be well tuned by the excitation power. As the laser power increases, the emission color changes from red to the green. Therefore, the coding capacity of the CdS branched barcodes can be well modulated by the temperature and pump laser power. Our studies demonstrate the possibility of using these branched nanostructures in multifunctional optical devices.