Effects related to deposition temperature of ZnCoO films grown by Atomic Layer Deposition - uniformity of Co distribution, structural, optical, electrical and magnetic properties

TL;DR

This study explores how deposition temperature affects the uniformity, structure, optical, electrical, and magnetic properties of ZnCoO films grown by Atomic Layer Deposition at temperatures below 300°C, highlighting the impact on Co distribution and magnetic behavior.

Contribution

It demonstrates that low-temperature ALD can produce uniform ZnCoO films with specific magnetic properties, and investigates how growth conditions influence Co distribution and phase formation.

Findings

High uniformity of ZnCoO films at 160°C with paramagnetic behavior.

Nonuniform films at 200°C show foreign phase formation and weak ferromagnetism.

Lower growth temperature reduces foreign phase formation and maintains paramagnetism.

Abstract

In the present study we report on properties of ZnCoO films grown at relatively low temperature by the Atomic Layer Deposition, using two reactive organic zinc precursors (dimethylzinc and diethylzinc). The use of these precursors allowed us the significant reduction of a growth temperature to below 300oC. The influence of growth conditions on the Co distribution in ZnCoO films, their structure and magnetic properties was investigated using Secondary Ion Mass Spectroscopy, Scanning Electron Microscopy, Cathodoluminescence, Energy Dispersive X-ray Spectrometry (EDX), X-ray diffraction and Superconducting Quantum Interference Device magnetometry. We achieved high uniformity of the films grown at 160{\deg}C. Such films are paramagnetic. Films grown at 200{\deg} and at higher temperature are nonuniform. Formation of foreign phases in such films was detected using high resolution EDX method. These samples are not purely paramagnetic and show weak ferromagnetic response at low temperature.