Synthesis, structural, and electrical characterization of RuO2 sol–gel spin-coating nano-films

G Lakshminarayana,T Nagao,I V Kityk

doi:10.1007/s10854-016-5184-z

Abstract

In this work a series of RuO2 thin films were synthesized through sol–gel spin coating processes and their structural and electrical properties are studied. The (1 1 0), (1 0 1), (2 0 0), and (2 1 1) characteristic peaks of RuO2 phase are identified from the annealed RuO2 films X-ray diffraction profiles. Through the Atomic Force Microscopy, the surface roughness values of the films evaluated as 1.2 nm, and 0.9 nm for 0.5, and 1.0 mmol RuO2 films, respectively. With Ru molar ratio increment the optical transparency of the synthesized films decreases in the UV–Vis-IR range. The P-type conductivity of RuO2 film is confirmed by Hall Effect measurement and the resistivity of 1.0 mmol RuO2 film annealed at 600 °C acquired by Hall measurement was 2.9 × 10−4 Ω cm. The synthesized RuO2 nano-thin films characterization demonstrates that an optically transparent conductive material can be reliably and efficiently created using simple sol–gel spin-coating methods.

Highlights

Ruthenium dioxide, RuO2, is a conductive ceramics that belongs to the family of transition metal oxides with tetragonal rutile-type structure
The P-type conductivity of RuO2 film is confirmed by Hall Effect measurement and the resistivity of 1.0 mmol RuO2 film annealed at 600 °C acquired by Hall measurement was 2.9 9 10-4 X cm
One of the most promising and important use of RuO2 is for the applications in organic light emitting devices (OLED), flat panel display and organic solar cells

Summary

Introduction

RuO2, is a conductive ceramics that belongs to the family of transition metal oxides with tetragonal rutile-type structure. One of the most promising and important use of RuO2 is for the applications in organic light emitting devices (OLED), flat panel display and organic solar cells This is because the ultrathin films of RuO2 are transparent and has high enough work function (5.2 eV) which realizes excellent hole conduction into the active layer of the device. The primary requirement here is the sufficiently high electrical conductance, high optical transparency, and smoothness as well as the closed nature of the film to avoid current leakage in the fabricated devices that promotes smooth growth of the organic layers. The latter two features are of particular importance to make low-wattage high-performance light emitting device or flat panel displays

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Conclusion