The present invention relates to a method of tuning an indium tin oxide (ITO) for hole injection in semiconductors, characterised by the steps of: dissolving cesium fluoride (CsF) in a deionised water at a concentration between 2-50 mg/L; coating the CsF solution on surface of a clean ITO glass; heating the coated ITO glass at temperature in a range of 85-150?C; cleaning the coated ITO glass with deionised water to remove cesium and residues; and drying the coated ITO glass to obtain the tuned ITO having a smoother ITO surface.