Internship proposal for a second-year master student Synthesis of quantum dots in III-V nanowires
Duration : 6 months starting from March
Salary ~ 600 EUR/month
Supervisor : Federico PANCIERA
Laboratory : Centre for Nanoscience and Nanotechnology (C2N), U. Paris-Saclay/CNRS
Web: https://elphyse.c2n.universite-paris-saclay.fr/en/

Contacts:

federico.panciera@c2n.upsaclay.fr

Context of the project : 

Semiconductor nanowires (NWs) exhibit unique properties that make them potential building blocks for a variety of next generation devices such as biosensors, solar cells, transistors, quantum light sources and lasers. In order to take advantage of the physical properties of NWs, it is crucial to control their geometry, crystal structure and doping. This goal will ultimately be achieved by a deep understanding of the growth mechanisms. The most common growth technique is the vapor-liquid-solid (VLS) method, where a liquid metal droplet catalyzes the growth of a solid NW from gas phase precursors. In this growth mode, the droplet plays a fundamental role in determining the structure of the nanowire, and the remarkable range of structures enabled by VLS can be thought of as the result of engineered changes to the droplet.
For example, growth of III-V semiconductor NWs using the VLS method can result in crystal structures different from their bulk phase. In GaAs NWs stable zincblende (ZB) phase coexists with metastable wurtzite (WZ) structure resulting in NWs having a mixed-phase structure. Remarkably, the valence and conduction bands of the two phases are misaligned so that small sections of one phase within the other effectively confine charge carriers.
Controlled switching between the two phases enables the synthesis of novel heterostructures, crystal-phase quantum dots (CPQD), with exceptional properties and potential applications in photonics [1] and quantum computing [2,3]. In contrast to compositional heterojunctions, CPQDs have intrinsically abrupt interfaces and
hence do not suffer from alloy intermixing at the interface, which hampers precise control of the electronic properties in compositional heterostructures.