Extremely Reduced Dielectric Constant and Band Gap Enhancement in Few-Layered Tungsten Disulfide Nanosheets

Highly crystalline few-layered tungsten disulfide (WS2) nanosheets were synthesized via a cost-effective, low-temperature hydrothermal route. X-ray diffraction and HR-TEM analysis confirmed the formation of hexagonal nanosheets with thickness of similar to 6-8 nm. Raman analysis and AFM results confirmed the few-layered 2H phase of WS2 nanosheets. The UV-vis study shows absorption peaks at 219 and 271 nm with large band gap value of similar to 3.12 eV for WS2 nanosheets. Surprisingly, WS2 nanosheets show a dielectric constant of approximately epsilon ' approximate to 5245, whereas bulk WS2 material exhibits a dielectric constant of 7482373. An almost 1426-fold decrease in the value of dielectric constant for the WS2 nanosheet is observed. Such an extreme reduction in dielectric constant and observance of large band gap in WS2 nanosheet were observed for the first time. The present study reveals the excellent and unusual optical and dielectric properties for their potential application in optoelectronic, dielectric, solar, phosphor, and various nanoelectronic devices.

Automated summary

Highly crystalline few-layered WS2 nanosheets were successfully synthesized via a low-temperature hydrothermal method. The WS2 nanosheets exhibited unique optical and dielectric properties, implying their potential applications.