Structural, Optical, and Electrical Characterization of ZnO and Al-doped ZnO Thin Films Deposited by MOCVD

A novel approach is used to deposit transparent Al-doped zinc oxide (AZO) films by metal-organic (MO) CVD using a Zn/Al safe, friendly to use, easily to handle, multimetal, liquid precursor source. Films are highly crystalline, (002) textured, and exhibit good transparency in the visible region (90%). The effects of Al doping on morphological, optical, and electrical performances are scrutinized. Al doping causes an energy gap (Eg) blue shift and a slight decrease in refractive index. Moreover, it favors sizeable changes in grain size and a surface integrity that are responsible for a reduced carrier mobility. Nevertheless, a minimum resistivity value of 5 x 10(-2) Omega cm is obtained for thin (similar to 150 nm) AZO films. Time resolved photoluminescence (TRPL) confirms the high crystal quality of deposited films. All features render present AZO films well suited for transparent conductive oxide (TCO) applications and suggest a great potential for the proposed fabrication method.