The effect of carbon-ion irradiation on surface microstructure and photoluminescence properties in monolayer tungsten diselenide

Defects in semiconducting transition-metal dichalcogenides (STMDs) are expected to significantly affect the physical properties of bulk material. In this paper, we explore the effect of defects in monolayer tungsten diselenide (WSe2) modified by ion irradiation. The monolayer WSe2 on Al2O3 was irradiated with a 1.0 MeV C+ ion source at fluences of 5.0 x 10(13) ions/cm(2) and 5.0 x 10(14) ions/cm(2). The surface morphology and binding energy before and after carbon-ion irradiation was analyzed using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The Raman spectra were measured in order to study the vibrational and the electronic properties of the material. Red shifting of the A(1)' and blue shifting of the E' modes were observed with monolayer WSe2 after carbon-ion irradiation. Meanwhile, in the photoluminescence (PL) spectra, we found that the bandgap can be effectively controlled. The change of the photoluminescence peak in monolayer WSe2 allows potential applications in a range of novel optoelectronic technologies.