SURFACE PROPERTIES OF INDIUM-TIN-OXIDE MODIFIED BY OXYGEN PLASMA IMMERSION ION IMPLANTATION

Indium tin oxide (ITO) was modified by oxygen inductive coupled plasma (O-ICP) and oxygen plasma immersion ion implantation (O-PIII) respectively to compare the effects of both techniques on the surface properties. X-ray photoelectron spectroscopy (XPS) was applied to characterize the electronic state of ITO surface. The oxygen content enhancement and band bending at the surface of ITO were found after treatment by both O-ICP and O-PIII. The surface work function of ITO thin film depends on the oxygen composition at the surface. A surface work function increment of 0.8 eV by O-PIII was estimated from the shift of O1s core levels to low binding energy, which was the double of that by O-ICP. The conductivity increment of ITO films was less than 1% after O-ICP and O-PIII treatment. The transparency of ITO films increased by about 1% resulted from surface texture by O-PIII sputtering.