Growth optimization and characterization of lattice-matched Al 0.82 In 0.18 N optical confinement layer for edge emitting nitride laser diodes H. Kim-Chauveau a,n , E. Frayssinet a , B. Damilano a , P. De Mierry a , L. Bodiou a , L. Nguyen a , P. Venne ´ gu  es a , J.-M. Chauveau a,b , Y. Cordier a , J.Y. Duboz a , R. Charash c , A. Vajpeyi c , J.-M. Lamy c , M. Akhter c , P.P. Maaskant c , B. Corbett c , A. Hangleiter d , A. Wieck e a CRHEA-CNRS, Rue B. Gregory, F-06560 Valbonne Sophia Antipolis, France b University of Nice Sophia Antipolis, Parc Valrose, F-06102 Nice Cedex 2, France c Tyndall National Institute, Lee Maltings, Cork, Ireland d Technische Universit¨ at Braunschweig, Mendelssohnstraße 2, 38106 Braunschweig, Germany e Lehrstuhl fuer Angewandte Festkoerperphysik Universitaetsstrasse 150, D-44780 Bochum, Germany article info Article history: Received 7 June 2011 Received in revised form 12 September 2011 Accepted 11 October 2011 Communicated by A. Bhattacharya Available online 17 October 2011 Keywords: A3. Metalorganic chemical vapor deposition B1. Nitrides B2. Semiconducting indium compounds B2. Semiconducting ternary compounds B3. Laser diodes abstract We present the growth optimization and the doping by the metal organic chemical vapor deposition of lattice-matched Al 0.82 In 0.18 N bottom optical confinement layers for edge emitting laser diodes. Due to the increasing size and density of V-shaped defects in Al 1x In x N with increasing thickness, we have designed an Al 1x In x N/GaN multilayer structure by optimizing the growth and thickness of the GaN interlayer. The Al 1x In x N and GaN interlayers in the multilayer structure were both doped using the same SiH 4 flow, while the Si levels in both layers were found to be significantly different by SIMS. The optimized 8  (Al 0.82 In 0.18 N/GaN¼54/6 nm) multilayer structures grown on free-standing GaN substrates were characterized by high resolution X-ray diffraction, atomic force microscopy and transmission electron microscopy, along with the in-situ measurements of stress evolution during growth. Finally, lasing was obtained from the UV (394 nm) to blue (436 nm) wavelengths, in electrically injected, edge-emitting, cleaved-facet laser diodes with 480 nm thick Si-doped Al 1x In x N/GaN multi- layers as bottom waveguide claddings. & 2011 Elsevier B.V. All rights reserved. 1. Introduction Among the group-III nitride alloys, Al 1 x In x N has recently attracted a great attention because it can be grown lattice- matched to GaN when the indium concentration is near x ¼ 18% [1]. This ternary alloy also renders large differences with respect to GaN in terms of band gap energy, refractive index and spontaneous polarization. These characteristics of lattice- matched Al 1 x In x N have paved the way towards many interesting applications for electronic and optoelectronic devices [2]. As one of the potential applications, Al 1 x In x N has been considered as an alternative to Al x Ga 1 x N as cladding in group III-nitrides laser diodes (LDs), especially for green wavelength emission [3–6]. Indeed, the refractive index contrast between the GaN waveguide and Al 0.1 Ga 0.9 N cladding diminishes as the emis- sion wavelength moves to the green range (Dn  0.053 for l ¼ 430 nm and Dn  0.035 at l ¼ 520 nm [7]), resulting in lower optical confinement in LD structures. In order to minimize the leakage of the guided optical modes into the high index GaN substrate, the increase of either the thickness or the Al composi- tion of the Al x Ga 1 x N cladding can be envisaged [8–10]. However, the increase of these two parameters is fairly limited due to the increasing tensile stress in Al x Ga 1 x N. For example, the Al content in Al x Ga 1 x N waveguide cladding layer is hardly higher than 10% (0.25% lattice mismatch), beyond which it suffers from severe cracking [9]. On the other hand, the lattice-matched Al 0.82 In 0.18 N ternary alloy can provide a large refractive index contrast to GaN (Dn  0.2 for l ¼ 430 nm and Dn  0.155 at l ¼ 520 nm) over the whole wavelength region [7], thus giving a better optical mode confinement while avoiding the strain issues. In fact, the Al 1x In x N epilayer has been successfully employed for distributed Bragg reflectors, which were used in vertical cavity surface emitting lasers and similar structures, and the breakthrough made by this group at the Ecole Polytechnique Fe ´de ´ rale de Lausanne should be acknowledged [2,5,6,11–15]. However, the growth of high quality Al 1x In x N is still challen- ging due to several intrinsic differences between the constituting binary compounds, AlN and InN. These two binaries present large Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/jcrysgro Journal of Crystal Growth 0022-0248/$ - see front matter & 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jcrysgro.2011.10.016 n Corresponding author. Tel.: þ33 04 93 95 42 17; fax: þ33 04 93 95 83 61. E-mail address: hc@crhea.cnrs.fr (H. Kim-Chauveau). Journal of Crystal Growth 338 (2012) 20–29