Experimental investigations of the bismuth oxide film grown by atomic layer deposition using triphenyl bismuth

Bismuth oxide thin films have been produced from the precursor of triphenyl bismuth and ozone by using the atomic layer deposition (ALD) technique. The growth rate of 0.23 Å/cycle is independent to deposition temperature at the range of 250 °C to 320 °C, and the self-limiting saturated adsorption of ALD for bismuth-source and oxygen-source precursors was verified. The films obtained in the ALD window (between 250 °C and 320 °C) have an indirect band gap of ~ 2.77 eV that is compatible with Bi2O3 − δ. High-resolution transmission electron microscopy reveals a mixed growth mode, horizontal growth initially, and subsequent vertical/island growth during the deposition process.