DOI: 10.17863/cam.121700
title: Research data supporting “Effect of buffer layer thickness on recombination in zincblende InGaN/GaN quantum wells”

description: Zincblende InGaN/GaN quantum wells grown along the [001] direction are free of the internal electric fields that limit the efficiency of conventional wurtzite InGaN-based quantum wells in the (0001) orientation. However, heteroepitaxial grown zincblende GaN often exhibit a significant density of stacking faults, which reduce the radiative recombination efficiency when they intersect the quantum wells (QWs). In this work we show that increasing the thickness of the buffer layer between substrate and InGaN/GaN quantum wells reduces the stacking faut density in the quantum wells and thereby increases the emission efficiency. Three sets of samples have been investigated X-ray diffraction (XRD), cathodoluminescence (CL) spectroscopy and photoluminescence (PL) spectroscopy. The first set of samples (series 1) consists of a single GaN buffer layer with thicknesses between 0.6 µm and 3.0 µm grown on 3C-SiC-on-Si substrates. Sample series 2 is based on a similar set of buffer layers with varying thicknesses, which was overgrown with a single InGaN/GaN qunatum well. In series 2 an InGaN-based single quantum well (SQW) structure was grown on a set of buffer layers with total thicknesses between 0.8 µm and 3.2 µm. Finally, series 3 is based on a similar set of buffer layers with varying thicknesses, which was overgrown with a multiple quantum well (MQW) structure. Further information on the sample structures and the experimental results can be found in the related research article. File: “Fig. 02” contains data from the XRD phase analysis for the first set of samples, consisting of buffer layers only. File: "Fig. 03 & 06" contains the HSPY files for the cathodoluminescence measurements on the SQW samples with varying buffer thickness between 0.8 µm to 3.2 µm. Python-based Jupyer Notebook is able to open the .hspy files, with HyperSpy and LumiSpy packages loaded. HyperSpy can be installed using Anaconda and LumiSpy using pip instructions. Jupyter Notebook will be installed automatically when installing Anaconda. Please find details in the links below: HyperSpy: https://hyperspy.org/hyperspy-doc/current/user_guide/install.html#anaconda-install LumiSpy: https://docs.lumispy.org/en/stable/user_guide/installation.html Anaconda: https://www.anaconda.com/download File: "Fig. 04 & 05" contains statistical analyses of the CL data for the SQW samples of series 2. The tab “Fig. 4a” contains the variation of density of SF-related dark stripes in CL maps with GaN buffer thickness parallel and perpendicular to the [1-10] miscut direction. The data in tab “Fig. 4b” shows the variation of mean area per bright patch with buffer thickness. The data in tab “Fig 5” are the room-temperature mean CL spectra of the zb-InGaN SQW samples of series 2. File: “Fig. 07-09” is an Excel file that contains the data of the PL analyses performed on the MQW samples of the third set of samples. The tab “Figure 7” contains low temperature (12 K) PL emission spectra measured at an excitation power density 10 W.cm^-2. The tab “Figure 8” contains PL transients for photon energies spanning the emission band of the MQW sample with 3.2 µm buffer layer. The tab “Figure 9”, contains the normalised temperature dependence of the spectrally integrated emission spectrum for the MQW sample with 3.2 μm buffer layer. The data of the inset show the intensity at 300 K relative to the intensity at 12 K for the MQW series as a function of buffer layer thickness.