On the Nitrogen Doping in Erbium and Nitrogen Codoped Magnesium Zinc Oxide Diode by Spray Pyrolysis

Chun-An Chen,Kai-Feng Huang,Mu-Chun Wang,Kuo-Jen Chang,Chien-Jung Huang,Yu-Ting Hsu,Wen-How Lan

doi:10.3390/cryst10010034

Abstract

Diodes with an erbium and nitrogen codoped magnesium zinc oxide (MgZnO:Er,N) active layer were fabricated by spray pyrolysis on Si substrate with aqueous solutions including magnesium nitrate, zinc acetate, erbium acetate, ammonium acetate, and indium nitrate precursors. Diodes with different nitrogen content in their precursor were prepared and their properties were investigated. With scanning electron microscopy, film surface with mixed hexagonal flakes and tiny blocks was characterized for all samples. Certain morphologies varied for samples with different N contents. In the photoluminescence analyses, the intensity of the oxygen-related defects peak increased with the increasing of nitrogen content. The diodes were fabricated with an Au and In deposition on the top and backside. The diode current–voltage as well as capacitance–voltage characteristics were examined. An ununiformed n-type concentration distribution with high concentration near the interface in the MgZnO:Er,N layer was characterized for all samples. Diodes with high nitrogen content exhibit reduced breakdown voltage and higher interface concentration characteristics. Under reversed bias conditions with an injection current of 50 mA, a light spectrum with two distinct green emissions around wavelengths 532 and 553 nm was observed. A small spectrum variation was characterized for diodes prepared from different nitrogen content. The diode luminescence characteristics were examined and the diode prepared from N/Zn=1 in the precursor showed an optimal injection current-to-luminescence property. The current and luminescence properties of the diode were characterized and discussed.

Highlights

Zinc oxide (ZnO), a group II–VI material, has been widely investigated in the past decades
In the Er doped diode, the energy transformation of carriers from impact ionization to Er ions was the origin of diode luminescence
As the Er (III) doping in ZnO and magnesium zinc oxide (MgZnO) (II–VI) shows an n-type contributor, sufficient Er doping could imply that the depletion width decreased with the increase of n-type concentration

Summary

Introduction

Zinc oxide (ZnO), a group II–VI material, has been widely investigated in the past decades. In the Er doped diode, the energy transformation of carriers from impact ionization to Er ions was the origin of diode luminescence. Diode performance improved with Mg incorporated in the pn diode structure [17] In this diode, the Er-related luminescence was operated under reverse bias with the impact ionization occurring in the depletion region. As the Er (III) doping in ZnO and MgZnO (II–VI) shows an n-type contributor, sufficient Er doping could imply that the depletion width decreased with the increase of n-type concentration. The Er and N codoped MgZnO diode was prepared with different N contents, and we compared the luminescence and diode properties

Experimental Section

Results and Discussions

Conclusions