Effect of GaN substrate thickness on the optical field of InGaN laser diodes

• J.A. Martín ^[2] ; M. Sánchez ^[1]
  1. [1] Universidad de La Habana

     Universidad de La Habana

     Cuba

     
  2. [2] Univesidad de Ciego de ávila "Máximo Gómez Báez"
• Localización: Revista Mexicana de Física, ISSN-e 0035-001X, Vol. 64, Nº. 3, 2018, págs. 254-260
• Idioma: inglés
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• Resumen

  • In this work the influence of GaN substrate thickness on the near and far-field patterns of InGaN lasers structures is numerically studied. In simulation a typical structure with an InGaN-MQW active region, GaN waveguide and Al_(x)Ga_(1−x)N cladding layers is considered. A fluctuating behavior was obtained showing that for some values of the substrate thickness the near and far-field patterns can be optimized, while there are critical values that significantly reduce the confinement factor and widen the far field patterns. It is also shown that, replacing the n-GaN contact layer by a graded- index (GRIN) Al_(x)Ga_(1−x)N layer can help reduce the optical field leakage to substrate. Simulation results indicate that properly choosing the thickness of the substrate and using a GRIN n- Al_(x)Ga_(1−x)N contact layer it is possible to improve both the confinement factor and far field patterns in nitride lasers.