abstract: III-V-bismide semiconductor alloys are a class of materials with applications in the mid and long wave infrared spectrum. The quaternary alloy InAsSbBi is attractive because it can be grown lattice-matched to commercially available GaSb substrates, and the adjustment of the Bi and Sb mole fractions enables both lattice constant and bandgap to be tuned independently. This dissertation provides a comprehensive study of the surface morphology and the structural and chemical properties of InAsSbBi alloys grown by molecular beam epitaxy. 210 nm thick InAsSbBi layers grown at temperatures from 280 °C to 430 °C on (100) on-axis, (100) offcut 1° to (011), and (100) offcut 4° to (111)A GaSb substrates are investigated using Rutherford back scattering, X-ray diffraction, transmission electron microscopy, Nomarski optical microscopy, atomic force microscopy, and photoluminescence spectroscopy. The results indicate that the layers are coherently strained and contain dilute Bi mole fractions. Large surface droplets with diameters and densities on the order of 3 µm and 106 cm-2 are observed when the growth is performed with As overpressures around 1%. Preferential orientation of the droplets occurs along the [011 ̅] step edges offcut (100) 1° to (011) substrate. The surface droplets are not observed when the As overpressure is increased to 4%. Small crystalline droplets with diameters and densities on the order of 70 nm and 1010 cm-2 are observed between the large droplets for the growth at 430°C. Analysis of one of the small droplets indicates a misoriented zinc blende structure composed of In, Sb, and Bi, with a 6.543 ± 0.038 Å lattice constant. Lateral variation in the Bi mole fraction is observed in InAsSbBi grown at high temperature (400 °C, 420 °C) on (100) on-axis and (100) offcut 4° to (111)A substrates, but is not observed for growth at 280 °C or on (100) substrates that are offcut 1° to (011). Improved crystal and optical quality is observed in the high temperature grown InAsSbBi and CuPtB type atomic ordering on the {111}B planes is observed in the low temperature grown InAsSbBi. Strain induced tilt is observed in coherently strained InAsSbBi grown on offcut substrates. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2020

Le Bismuth, un élément V, a longtemps été négligé dans la famille des semi-conducteurs III V. Toutefois, les matériaux bismures connaissent un intérêt croissant depuis le début des années 2000, principalement en raison de l’exceptionnelle réduction de l’énergie de bande interdite couplée à la forte augmentation de l’énergie entre la bande de valence et la bande de spin-orbite introduites par l’atome de Bismuth. Parmi les alliages III-V-Bi, le GaSbBi est particulièrement intéressant pour l’émission dans la gamme de longueurs d’onde entre 2 et 5 µm. Jusqu’à présent, ce matériau n’a été que très peu étudié, principalement à cause des difficultés d’incorporation du Bismuth. En effet, l’incorporation du Bismuth dans les matériaux III-V nécessite des conditions de croissance très spécifiques et inhabituelles. Dans ce contexte, l’objectif premier de cette thèse est d’étudier l’épitaxie par jet moléculaire et les propriétés du GaSbBi.Ainsi, l’influence des différents paramètres de croissance sur l’incorporation du Bismuth a été étudiée minutieusement. Ces expériences ont permis la réalisation de couches de GaSbBi à forte teneur en Bismuth démontrant une excellente qualité cristalline. La plus importante concentration de Bismuth atteinte est de 14%, ce qui constitue encore aujourd’hui le record mondial dans GaSb. Par ailleurs, une réduction de l’énergie de bande interdite de 28 meV/%Bismuth a été observée. Des puits quantiques GaSbBi/GaSb, émettant jusqu’à 3.5 µm à température ambiante ont ensuite été épitaxiés et caractérisés. Le premier laser à base de GaSbBi a également été réalisé. Ce composant fonctionne en continu à 80 K et une émission laser pulsée a été observée proche de 2.7 µm à température ambiante. Enfin, un autre alliage bismure méconnu, le GaInSbBi, a été épitaxié. L’influence de l’Indium sur l’incorporation du Bismuth et les propriétés de puits quantiques GaInSbBi/GaSb ont été étudiées. / Bismuth, a group-V element, has long been neglected in the III-V semiconductor family. However, dilute bismides started to attract great attention since the early 2000s, due to the giant bandgap reduction and the strong increase of the spin-orbit splitting energy introduced by the incorporation of Bismuth. Among the III-V-Bi alloys, GaSbBi is particularly interesting but has only been sporadically studied, mainly due to the very challenging incorporation of Bismuth. Bismuth requires indeed very unusual growth conditions to be incorporated into III-V materials. The main objective of this thesis was to investigate the molecular beam epitaxy and the properties of GaSbBi alloys and heterostructures.A careful study of the influence of the different growth parameters on the Bismuth incorporation was first carried out. These investigations lead to the fabrication of high quality GaSbBi layers and to the incorporation of 14% Bismuth, the highest content reached in GaSb so far. A bandgap reduction of 28 meV/%Bismuth was observed. GaSbBi/GaSb multi quantum-wells structures with various thicknesses and compositions were then fabricated and exhibited photoluminescence emission up to 3.5 µm at room-temperature. The first GaSbBi-based laser diode was also fabricated, demonstrating continuous wave operation at 80 K and a room-temperature emission close to 2.7 µm under pulsed excitation. Finally, the growth of another dilute bismide alloy, GaInSbBi, was investigated. The influence of the Indium atoms on the incorporation of Bismuth was particularly studied together with the properties of GaInSbBi/GaSb multi quantum-wells structures.