Peculiarities of Electric and Dielectric Behavior of Ni- or Fe-Doped ZnO Thin Films Deposited by Atomic Layer Deposition

TL;DR

This paper studies how adding Ni or Fe to ZnO thin films affects their electric and dielectric properties using atomic layer deposition.

Contribution

The study reveals distinct polarization mechanisms in Ni- and Fe-doped ZnO thin films using ALD.

Findings

Ni and Fe doping significantly alters the electric and dielectric behavior of ZnO thin films.

Different polarization mechanisms dominate in Ni- and Fe-doped films.

Spectral ellipsometry confirmed changes in the optical bandgap due to doping.

Abstract

The physical properties of ZnO can be tuned efficiently and controllably by doping with the proper element. Doping of ZnO thin films with 3D transition metals that have unpaired electron spins (e.g., Fe, Co, Ni, etc.) is of particular interest as it may enable magnetic phenomena in the layers. Atomic layer deposition (ALD) is the most advanced technique, which ensures high accuracy throughout the deposition process, producing uniform films with controllable composition and thickness, forming smooth and sharp interfaces. In this work, ALD was used to prepare Ni- or Fe-doped ZnO thin films. The dielectric and electrical properties of the films were studied by measuring the standard current–voltage (I–V), capacitance–voltage (C–V), and capacitance–frequency (C–f) characteristics at different temperatures. Spectral ellipsometry was used to assess the optical bandgap of the layers. We established that the dopant strongly affects the electric and dielectric behavior of the layers. The results provide evidence that different polarization mechanisms dominate the dielectric response of Ni- and Fe-doped films.

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