Structure and optical properties of polyvinyle alcohol capped GaAs nanocrystals

Polyvinyl alcohol capped GaAs nanocrystals, assembled in thin film form, have been synthesized by a simple electrochemical technique. Transmission electron microscopy (TEM) study reveals the presence of 20-50 nm size GaAs nanoparticles embedded in the polymer host. Selected area diffraction pattern contains a series of spotted rings indicative of textured nature of the thin film. The excitonic peak broadening and the blue shift of its spectral position with respect to the bulk band gap depend upon the concentration of the polyvinyle alcohol. The X-ray photoelectron spectrum shows C(1s) peak corresponding to the surface bonded polyvinyl alcohol along with the Ga3d and As3d peaks of the GaAs core. Room temperature micro-Raman spectrum shows one surface phonon mode that shifts to the lower energy side with decrease in the crystallite size.