Crystal growth and properties of LiAlO2 and nonpolar GaN on LiAlO2 substrate

Abstract

In this study, the growth and properties of LiAlO2 material and a nonpolar GaN-based light-emitting-diode (LED) structure on LiAlO2 have been investigated. The LiAlO2 material is grown by the Czochralski pulling technique and is used as a substrate for nonpolar nitride growth. An improved surface roughness can be obtained by a four-step polishing process. With subsequent nitridation treatment, a pure M-plane (101̱0) GaN can be obtained. An electron microscope shows an abundance of cracks that are oriented parallel to the (001) and (100) planes of the LiAlO2 substrate on the rear surface of GaN. The absence of the polarization-induced electric field of a GaN-based LED structure on LiAlO2 was shown by using photoluminescence measurements. Therefore, this approach is promising to further increase the luminescence performance of GaN-based LEDs.

Optical characteristics of m-plane InGaN/GaN multiple quantum well grown on LiAlO2 (100) by MOVPE

“…Such built-in electric fields can be avoided by growing GaN films along nonpolar directions, such as (1 0 1 0)-oriented (m-plane) films, which would lead to a more efficient recombination across the entire well of a QW structure. Recently, growth of m-plane GaN on LiAlO 2 substrates has attracted much attention [5][6][7][8]. The LiAlO 2 crystal structure is tetragonal with lattice parameters a=b= 5.1687 Å , and c=6.2679 Å , which nicely match c GaN and 2a GaN , respectively.…”

A-plane GaN layer grown on (302) (-LiAlO2 by MOCVD

“…Also the m-plane InGaN/GaN multiple quantum wells (MQW) have been grown on the substrate by molecular-beam epitaxy [8][9][10], and non-polar LED structures have been grown by metal organic chemical vapor deposition (MOCVD) on LiAlO 2 (1 0 0) [11,12]. The device performance of the m-plane LEDs on LAO (1 0 0) has been reported [13,14].…”

Growth and characterization of m-plane GaN-based layers on LiAlO2 (100) grown by MOVPE

“…To overcome this problem, it has been proposed to grow GaN films with nonpolar planes, such as (11 2 0) (a-plane), (1 0 1 0) (m-plane), and (11 0 2) (r-plane), which would lead to a more efficient recombination across the entire well of a quantum well (QW) structure. The recent development of the utilization of LiAlO 2 substrates has attracted a lot of attention [5][6][7][8]. LiAlO 2 single crystal has a tetragonal structure with lattice parameters a ¼ b ¼ 5.1687 Å , and c ¼ 6.2679 Å , which are close to c GaN and 2a GaN , respectively.…”