Article

Phase separation suppression in InGaN epitaxial layers due to biaxial strain

Universität Paderborn, Paderborn, North Rhine-Westphalia, Germany
Applied Physics Letters (Impact Factor: 3.52). 03/2002; 80(5):769 - 771. DOI: 10.1063/1.1436270
Source: IEEE Xplore

ABSTRACT Phase separation suppression due to external biaxial strain is observed in In x Ga 1-x N alloy layers by Raman scattering spectroscopy. The effect is taking place in thin epitaxial layers pseudomorphically grown by molecular-beam epitaxy on unstrained GaN(001) buffers. Ab initio calculations carried out for the alloy free energy predict and Raman measurements confirm that biaxial strain suppress the formation of phase-separated In-rich quantum dots in the In x Ga 1-x N layers. Since quantum dots are effective radiative recombination centers in InGaN, we conclude that strain quenches an important channel of light emission in optoelectronic devices based on pseudobinary group-III nitride semiconductors. © 2002 American Institute of Physics.

Full-text

Available from: Lara K. Teles, Apr 26, 2015
1 Follower
 · 
153 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Through designing the quantum well (QW) structure by introducing the InGaN interlayers into the GaN barriers, the compressive strain magnitude is significantly decreased. Two distinct emission peaks corresponding to In-rich localized state and quantum well ground state emissions observed from the electroluminescence (EL) spectra demonstrate that the phase separation is enhanced to form In-rich localized states in the original structure with larger strain, but no significant phase separation is observed in the designed structures with less strain. This abnormal phenomenon is contrary to the previous reports that phase separation in the InGaN layer can be suppressed by compressive strain. Therefore, it is suggested that the strain-driven kinetic phase separation should be taken into account in our case to more fully and precisely understand the role played by strain on phase separation that strain can hinder the phase separation thermodynamically but may drive phase separation kinetically.
    Solid State Communications 09/2014; 194. DOI:10.1016/j.ssc.2014.03.011 · 1.70 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have carried out a theoretical study for calculating the electronic and optical properties of InxGa1-xN/GaN(001) superlattices with short periodicity, while In composition is altered from 0 to 100 %. These appealing systems have been simulated using ab initio method in the framework of full-potential linearized augmented plane wave scheme. In this respect, a modified Becke-Johnson for the exchange and correlation potential term is included for describing adequately the energy gap of these promising low-dimensional materials. Exclusively, we computed the density of states, imaginary part of dielectric function, refractive index and absorption coefficient. However, it is viable to control the optical properties of these superlattices which may be useful for optoelectronic devices application.
    Applied Physics A 11/2014; 117(3):1451-1460. DOI:10.1007/s00339-014-8573-2 · 1.69 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In order to investigate the influence of compressive strain on indium incorporation in InAlN and InGaN ternary nitrides, InAlN/GaN heterostructures and InGaN films were grown by metal–organic chemical vapor deposition. For the heterostructures, different compressive strains are produced by GaN buffer layers grown on unpatterned and patterned sapphire substrates thanks to the distinct growth mode; while for the InGaN films, compressive strains are changed by employing AlGaN templates with different aluminum compositions. By various characterization methods, we find that the compressive strain will hamper the indium incorporation in both InAlN and InGaN. Furthermore, compressive strain is conducive to suppress the non-uniform distribution of indium in InGaN ternary alloys.
    Chinese Physics B 01/2015; 24(1). DOI:10.1088/1674-1056/24/1/017302 · 1.39 Impact Factor