Thickness Study of Er-Doped Magnesium Zinc Oxide Diode by Spray Pyrolysis

Yu-Ting Hsu,Kai-Feng Huang,Kuo-Jen Chang,Mu-Chun Wang,Jia-Ching Lin,Shao-Yi Lee,Wen-How Lan,Chien-Jung Huang,Che-Chi Lee,Wen-Jen Lin

doi:10.3390/cryst8120454

Abstract

Erbium-doped magnesium zinc oxides were prepared through spray pyrolysis deposition at 450 °C with an aqueous solution containing magnesium nitrate, zinc acetate, erbium acetate, and indium nitrate precursors. Diodes with different erbium-doped magnesium zinc oxide thicknesses were fabricated. The effect of erbium-doped magnesium zinc oxide was investigated. The crystalline structure and surface morphology were analyzed using X-ray diffraction and scanning electron microscopy. The films exhibited a zinc oxide structure, with (002), (101), and (102) planes and tiny rods in a mixed hexagonal flakes surface morphology. With the photoluminescence analyses, defect states were identified. The diodes were fabricated via a metallization process in which the top contact was Au and the bottom contact was In. The current–voltage characteristics of these diodes were characterized. The structure resistance increased with the increase in erbium-doped magnesium zinc oxide thickness. With a reverse bias in excess of 8 V, the light spectrum, with two distinct green light emissions at wavelengths of 532 nm and 553 nm, was observed. The light intensity that resulted when using a different operation current of the diodes was investigated. The diode with an erbium-doped magnesium zinc oxide thickness of 230 nm shows high light intensity with an operational current of 80 mA. The emission spectrum with different injection currents for the diodes was characterized and the mechanism is discussed.

Highlights

Rare-earth-doped materials have been widely investigated in many applications in past decades [1,2,3,4,5]
We investigated the diode performance of the zinc oxide (ZnO):Er on a p-Si substrate by spray pyrolysis method in the previous study [22]
Heterostructured p-Si/MgZnO:Er/ZnO:In diodes with different MgZnO:Er active layer thicknesses were prepared by spray pyrolysis

Summary

Introduction

Rare-earth-doped materials have been widely investigated in many applications in past decades [1,2,3,4,5]. The emission wavelength is in the low transmission loss window of PMMA-core optical fiber [11]. This is promising for the development of similar diodes as the emission source in Si-based photonic applications [12]. In the operation of the Er-doped ZnO diode, an operational voltage in excess of the reverse bias breakdown condition is needed to achieve the carrier impact ionization condition to transfer the energy to Er-related emissions [9]. We investigated the diode performance of the ZnO:Er on a p-Si substrate by spray pyrolysis method in the previous study [22]. The effect of the injection current on diode electroluminescence intensity and spectral properties was studied

Experimental

Results and Discussion

Conclusions