Final PhD Seminar

III-V semiconductor nanowires (NWs) are gradually considered as building blocks for the future optoelectronic devices thanks to their unique properties, such as superior optical quality, freedom in forming complex heterostructure and possibility of integration with Si. Compared with standard III-As and III-P based NWs, III-Sb NWs and related heterostructures have not been fully developed. As a surfactant, Sb could be used to study NW growth fundamental under surface engineering. In addition, III-Sb semiconductors present unbeaten properties, such as the largest electron and hole mobility, the narrowest bandgap, large g-factor, strong spin-orbit interaction and capability in forming different types of band alignment. As a consequence, III-Sb NWs are highly suitable for infrared photodetection, ultra-fast and low power optoelectronic devices and quantum physics study applications. Therefore, it is essential to gain understanding of III-Sb NW growth and push the development of III-Sb NWs for device applications.

This thesis starts with the understanding of Sb surfactant role in growing III-V semiconductor nanowires. Sb surfactant leads to difficulties in growing [111]B polar GaSb and ternary GaAs_1-xSb_x nanowires. On the contrast, Sb surfactant property is beneficial in growing GaAs and GaAs_1-xSb_x nanowires in the [111]A polar direction. These researches deepen the fundamental mechanism of nanowire growth. Utilizing the growth understanding, high quality GaAs_1-xSb_x nanowires, GaAs_1-xSb_x /InP core/shell nanowires and GaAs_1-xSb_x quantum well nanowire tubes are grown and optimized with superior optical qualities in the near infrared range (1.3~1.55 μm), showing potential applications in the near infrared photodetector and low threshold nanowire lasing.