Growth and characterization of InxGa1−xN (0 < x < 0.16) templates for controlled emissions from MQW

Abstract

InxGa1−xN (0 < x < 0.16) templates were grown by Metal Organic Chemical Vapor Deposition (MOCVD) using the semibulk (SB) growth approach. We have studied the impact of different SB design parameters such as the number of (InGaN/GaN) periods, InGaN layer thickness (T), and the GaN substrate quality on the SB-template properties, and its degree of relaxation. SIMS characterization measured the variation of indium content (x) in the template, while photoluminescence reflected the indium content at the topmost layers of the SB template. X-ray diffraction techniques measured the average lattice parameters and degree of strain relaxation through the entire InxGa1−xN SB-templates. The SB approach results in superior material quality relative to the bulk grown InGaN, mainly due to its ability to avoid the inclusion of indium-rich clusters and V-pits in the SB templates. The SB approach slows down the relaxation processes and templates as thick as 750 nm are not fully relaxed. We are reporting on methods to enhance the relaxation processes in InxGa1−xN SB-templates. Finally, when InxGa1−xN templates with 0 ≤ x ≤ 0.16 are used as substrates for InGaN/GaN multiple quantum wells, the emission wavelength is shifted from blue to green by changing the indium content in the InxGa1−xN SB-templates. To the best of our knowledge, the current results present the highest indium content reported in InxGa1−xN SB-templates.