Enhanced Doping Efficiency of Al-Doped ZnO by Atomic Layer Deposition Using Dimethylaluminum Isopropoxide as an Alternative Aluminum Precursor

Atomic layer deposition offers the unique opportunity to control, at the atomic level, the 3D distribution of dopants in highly uniform and conformal thin films. Here, it is demonstrated that the maximum doping efficiency of Al in ZnO can be improved from ∼10% to almost 60% using dimethylaluminum isopropoxide (DMAI, Al(CH3)2(O i Pr)) as an alternative Al precursor instead of the conventionally used trimethylaluminum (TMA, Al(CH3)3). Due to the steric hindrance of the isopropoxyl ligand of the precursor, the Al atoms can be deposited more widely dispersed, which enables higher active-dopant densities and hence a higher conductivity of the Al-doped films.