Intitulé Etude et simulation d’un laser à semiconducteur à puits quantique (Study and simulation of a semiconductor single quantum well laser).

Abstract

Nowadays, the development of short wavelength lasers which can emit coherent light in green, blue, violet, and ultraviolet (UV) regimes become one of the most important challenges in the field of optoelectronics, and in particular, those made by III-nitride wide bandgap materials. During this thesis, a modelling of a wurtzite compressive strain quantum well nanostructure laser based on III-nitride GaN/AlxGa1-xN was achieved by the use of ATLAS of SILVACO TCAD simulation software. The main focus of this research work was to study the effect of the quantum well (QW) width, carrier density, and Aluminum (Al) concentration in the barrier layers on the optical (optical gain, spontaneous emission and the power spectral density) and electrical characteristics of a gallium nitride (GaN)-based QW laser diode, which is investigated by means of a careful modelling analysis in a wide range of temperature, all by using two different approaches for the calculation of energy band edges and effective masses, where in the first we assume the conduction and valence bands are parabolic, however, the second model consider the non-parabolicity of the bands and computed via 6×6 band k.p formalism. The results allow us to say that, by the use k.p method, we can get more accurate results that are expressed as a more significant optical gain with low threshold current density operating at high temperatures and emitting in the ultraviolet (UV) regime.