Morphological impact of zinc oxide layers on the device performance in thin-film transistors

Abstract

Zinc oxide thin-films are prepared either by spin coating of an ethanolic dispersion of nanoparticles (NP, diameter 5 nm) or by spray pyrolysis of a zinc acetate dihydrate precursor. High-resolution electron microscopy studies reveal a monolayer of particles for the low temperature spin coating approach and larger crystalline domains of more than 30 nm for the spray pyrolysis technique. Thin-film transistor devices (TFTs) based on spray pyrolysis films exhibit higher electron mobilities of up to 24 cm² V⁻¹s⁻¹ compared to 0.6 cm² V⁻¹s⁻¹ for NP based TFTs. These observations were dedicated to a reduced number of grain boundaries within the transistor channel.