Abstract
In this report, comparative investigation of photoluminescence (PL) characteristics of CdS nanobelts (NBs) and nanowires (NWs) is presented. At low temperatures, emissions originate from radiative recombination of free exciton A, neutral donor bound exciton, neutral acceptor bound exciton and surface related exciton (SX) are observed and analyzed through power-dependent and temperature-dependent PL measurements. We found that SX emission takes a predominant role in emissions of CdS nanobelts and nanowires. There is a direct correlation between SX emission intensity and surface-to-volume ratio, which is the SX emission intensity is proportional to the superficial area of the nanostructures. At the same time, we found that the exciton-phonon interaction in the CdS NWs sample is weaker than that of CdS NBs sample. Furthermore, lasing action has been observed in CdS NBs sample at room temperature with lasing threshold of 608.13 mW/cm2. However, there is no lasing emission in CdS NWs sample. This phenomenon can be explained by the side effects (such as thermal effects) from surface deep level transitions caused the lower damage threshold in CdS NWs. Based on the observations and deductions presented here, SX emission significantly impact on the performance of nanostructures for lasing and light-emitting applications.
Highlights
Low-dimensional nanomaterials play an important role in photonic devices
The corresponding peaks located at 2.552, 2.539, and 2.530 eV can be labeled as free exciton A (FXA), neutral donor-bound exciton emission (D0X) and neutral acceptor bound exciton (A0X), respectively
It is worth mentioning that the surface related exciton (SX) emission intensity of CdS NWs sample is about two times higher than that of CdS NBs sample
Summary
Low-dimensional nanomaterials play an important role in photonic devices. Many research have been carried out to characterize their unprecedented properties derived from their quantum size in at least one dimension or strong anisotropy [1,2,3,4]. The richness of nanostructures facilitates the observation of various interesting phenomena, which allows the integration of functional nanomaterials into a wide range of applications. Due to the large surface-to-volume ratio, the optical properties of low-dimensional semiconductors are strongly affected by the material quality and surface morphology. Various low-dimensional semiconductors are used in micro/nano-devices, such as CdS, ZnO, ZnS, and GaAs, etc. As one of the most important applications, laser devices with low threshold, high reliability, and good stability are highly desired. Research on the nanostructure-based laser devices has focused on the
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
