The Phase Evolution and Physical Properties of Binary Copper Oxide Thin Films Prepared by Reactive Magnetron Sputtering.

Weifeng Zheng,Yingbin Lin,Kehua Zhong,Yue Chen,Zhigao Huang,Xihong Peng

doi:10.3390/ma11071253

Weifeng Zheng, Yingbin Lin + Show 4 more

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https://doi.org/10.3390/ma11071253

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Abstract

P-type binary copper oxide semiconductor films for various O2 flow rates and total pressures (Pt) were prepared using the reactive magnetron sputtering method. Their morphologies and structures were detected by X-ray diffraction, Raman spectrometry, and SEM. A phase diagram with Cu2O, Cu4O3, CuO, and their mixture was established. Moreover, based on Kelvin Probe Force Microscopy (KPFM) and conductive AFM (C-AFM), by measuring the contact potential difference (VCPD) and the field emission property, the work function and the carrier concentration were obtained, which can be used to distinguish the different types of copper oxide states. The band gaps of the Cu2O, Cu4O3, and CuO thin films were observed to be (2.51 ± 0.02) eV, (1.65 ± 0.1) eV, and (1.42 ± 0.01) eV, respectively. The resistivities of Cu2O, Cu4O3, and CuO thin films are (3.7 ± 0.3) × 103 Ω·cm, (1.1 ± 0.3) × 103 Ω·cm, and (1.6 ± 6) × 101 Ω·cm, respectively. All the measured results above are consistent.

Highlights

P-type binary copper oxide semiconductors with different morphologies and copper oxidation states have three distinct phases: cuprous oxide (Cu2 O), paramelaconite (Cu4 O3 ), and tenorite (CuO) [1,2]
Cu2 O has the advantage of good transparency in the visible light range, its low carrier concentration or large resistivity leads to poor performances [3,10]
1a shows the XRD patterns for pure phase Cu2 O, Cu4 O3, and CuO deposited at 0.5 Pa with the flowing of 8 sccm, 14 patterns sccm, and sccm, respectively

Summary

Introduction

P-type binary copper oxide semiconductors with different morphologies and copper oxidation states have three distinct phases: cuprous oxide (Cu2 O), paramelaconite (Cu4 O3 ), and tenorite (CuO) [1,2]. They have great application potential in thin-film devices such as solar cell [3] and thin-film lithium-ion battery [2]. The band structure of Cu2 O, with a direct gap range from 2.1 to 2.6 eV [7,10,11,12], was experimentally well established. Cu2 O has the advantage of good transparency in the visible light range, its low carrier concentration or large resistivity leads to poor performances [3,10]

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Conclusion