Charge transport, optical transparency, microstructure, and processing relationships in transparent conductive indium-zinc oxide films grown by low-pressure metal-organic chemical vapor deposition

Indium-zinc oxide films (ZnxInyOx+1.5y), with x/y=0.08-12.0, are grown by low-pressure metal-organic chemical vapor deposition using the volatile metal-organic precursors In(TMHD)(3) and Zn(TMHD)(2) (TMHD = 2,2,6,6-tetramethyl-3,5 -heptanedionato). Films are smooth (rms roughness=40-50 Angstrom) with complex microstructures which vary with composition. The highest conductivity is found at x/y=0.33, with sigma=1000 S/cm (n -type; carrier density=3.7x10(20) cm(3); mobility=18.6 cm(2)/V s; d sigma/dT<0). The optical transmission window of such films is broader than Sn-doped In2O3, and the absolute transparency rivals or exceeds that of the most transparent conductive oxides. X-ray diffraction, high resolution transmission electron microscopy, microdiffraction, and high resolution energy dispersive X-ray analysis show that such films are composed of a layered ZnkIn2O3+k phase precipitated in a cubic In2O3:Zn matrix. (C) 1998 American Institute of Physics.