Improved performance of electroluminescence in a n-ZnO microrod/p-GaN-based light-emitting diodes with SiO2 inserting nanolayer

Abstract

Zinc oxide (ZnO) has a wide band-gap (3 37eV) and also a large exciton binding energy (60meV) which makes it valuable for short wavelength UV light emitting diodes (LED) and laser device As a construction material GaN are often chosen due to its little lattice mismatch and crystallographic similarity with ZnO A ZnO microrod has an advantage in its hexagonal microcavity which provides a superior resonant cavity for the light confinement To enhance emitting intensity an intermedium layer between the ZnO microrod and p-GaN thin film was employed Here we demonstrate an intense UV polarized single horizontal n-ZnO microrod/p-GaN heterojunction light-emitting diodes with a sandwiched SiO2 layer The characterization of the fabricated device shows good diode behavior with low turn-on voltage of 4 5 V and strong electroluminescence (EL) intensity with dominant peak of 392 nm under the operation of forward injection currents The enhanced EL performance is associated with optical confinement and carrier confinement effects by inserting SiO2 intermediate layer The origin of EL emission bands can be confirmed by polarization-resolved EL measurement

Date of Award	2016 Aug 15
Original language	English
Supervisor	Hsu-Cheng Hsu (Supervisor)