Using Modified-Intake Plasma-Enhanced Metal-Organic Chemical Vapor Deposition System to Grow Gallium Doped Zinc Oxide.

Po-Hsun Lei,Yuan-Yu Zhan,Jia-Jan Chen,Zong-Lin Jiang,Ming-Hsiu Song

doi:10.3390/mi12121590

Po-Hsun Lei, Yuan-Yu Zhan + Show 3 more

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https://doi.org/10.3390/mi12121590

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Journal: Micromachines	Publication Date: Dec 20, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: National Formosa University

Abstract

We have used a modified-intake plasma-enhanced metal–organic chemical vapor deposition (MIPEMOCVD) system to fabricate gallium-doped zinc oxide (GZO) thin films with varied Ga content. The MIPEMOCVD system contains a modified intake system of a mixed tank and a spraying terminal to deliver the metal–organic (MO) precursors and a radio-frequency (RF) system parallel to the substrate normal, which can achieve a uniform distribution of organic precursors in the reaction chamber and reduce the bombardment damage. We examined the substitute and interstitial mechanisms of Ga atoms in zinc oxide (ZnO) matrix in MIPEMOCVD-grown GZO thin films through crystalline analyses and Hall measurements. The optimal Ga content of MIPEMOCVD-grown GZO thin film is 3.01 at%, which shows the highest conductivity and transmittance. Finally, the optimal MIPEMOCVD-grown GZO thin film was applied to n-ZnO/p-GaN LED as a window layer. As compared with the indium–tin–oxide (ITO) window layer, the n-ZnO/p-GaN LED with the MIPEMOCVD-grown GZO window layer of the rougher surface and higher transmittance at near UV range exhibits an enhanced light output power owing to the improved light extraction efficiency (LEE).

Highlights

The MIPEMOCVD-grown gallium-doped zinc oxide (GZO) thin films with varied Ga content of 1.59 to 5.42 at% can be obtained by adjusting the flow rate and temperature of the TEGa source
These defects distorted the local order of the crystal structure of the MIPEMOCVD-grown GZO thin films and led to a decrease in the (002) peak intensity as compared with zinc oxide (ZnO) thin film [2]
Because the crystalline structure of the ZnO thin films was distorted owing to the doping of Ga atoms, the intensities of the (100) and (101) peaks for the MIPEMOCVD-grown GZO thin films were more obvious than those of the peaks for the intrinsic ZnO thin film

Summary

Introduction

Zinc oxide (ZnO)-based materials have attracted increasing attention for decades because of their low cost, nontoxicity, wide direct band gap, large exciton binding energy, high optical transmittance in the visible range, and stable thermochemical properties [1,2]. These remarkable materials and optoelectronic characteristics render ZnO-based materials useful in various applications such as light-emitting diodes (LEDs), solar cells, photodetectors, gas and flame sensors, missile launch detection, photocatalysts, and transparent conductive oxides (TCOs) [3,4,5,6,7,8].

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