Facile, single step synthesis of CdS-RGO heterostructure and its photo enhanced field emission investigations

CdS-RGO heterostructure was synthesized by a thermal evaporation method and characterized using x-ray diffraction, SEM, TEM, photoluminescence spectroscopy (PL) and Raman spectroscopy so as to reveal its structural, compositional and electronic properties, prior to field emission (FE) investigations. The FE characteristics with and without visible illumination of the CdS-RGO heterostructure planar emitter were measured at base pressure 1 x 10(-8) mbar. The values of turn-on field, corresponding to emission current density of 1 mu A/cm(2) without and with illumination, are found to be 2.3 and 2.0 V mu m(-1), respectively. Furthermore, under pulsating illumination, the emitter exhibits emission current pulses depicting nearly four times enhancement in the emission current, with rise and fall time constants as 4.4 and 6.4 s, respectively. The photoenhanced FE behaviour is attributed to the modulation of electronic properties due to the CdS nanostructures. The results obtained herein propose the CdS-RGO heterostructure emitter as a photo-sensitive field emission switch in next generation optoelectronic nanodevices.