Epitaxial III-V/Si heterojunctions for photonic devices.

Monolithic integration of III-V materials on silicon is of great interest for efficient electronic-photonic integrated devices and multijunction solar cells on silicon. However, defect formation in the heteroepitaxial layers due to lattice mismatch, thermal mismatch, and polarity mismatch makes it a great challenge. In this work, high quality III/V epitaxial layers are realised on Si by epitaxial lateral overgrowth (ELOG) and corrugated epitaxial lateral overgrowth (CELOG) techniques using a hydride vapour phase epitaxy (HVPE) reactor. We demonstrate electroluminescence of multi quantum well structure grown on InP/Si by ELOG and photodiode behaviour of CELOG n-InP/p-Si. Extensive characterization of CELOG InP/Si and CELOG GaxIn1-xP/Si is also the main subject of this thesis. This includes X-ray diffraction, (time resolved) photoluminescence, Raman spectroscopy, cathodoluminescence and scanning and transmission electron microscopies. A wafer-scale InP layer is obtained on a 3” Si wafer via ELOG. The ELOG InP/Si is then used as a substrate to fabricate a multi quantum well LED emitting at 1530 nm. Although the MQWs were grown on InP covering ELOG InP layer and InP layer on the defective seed, rather strong luminescence is observed from the electrically injected MQW on InP/Si. We identify that unsatisfactory surface morphology after MQW growth as the main factor yielding broad emission without leading to stimulated emission. However transparency condition measurements reveal that there is gain in the material indicating the potential of this technique for fabricating lasers on silicon. We need to address also the warping of ELOG/Si due to thermal strain in the device processing. CELOG of InP/Si revealed a highly crystalline InP layer on Si with an abrupt interface free of dislocations despite an 8% lattice mismatch. That misfit dislocations are confined to the interface and do not lead to threading dislocations in the layer is characteristic of the wafer bonded interface. We find the same behaviour in our CELOG ...