Hexagonal SiGe for photonics
Host organizations
Hiring Institution
École Centrale de Lyon (EC Lyon)
PhD-Awarding Institutions
École Centrale de Lyon (EC Lyon)
RMIT University (RMIT)
Position Description
Proposed projects
Option 1
Hexagonal SiGe Laser on silicon substrate
In the field of silicon photonics, the critical missing device is a monolithic light source completely compatible with complementary-metal-oxide-semiconductor (CMOS) technologies. This is a straightforward consequence of the indirect bandgap of cubic Si semiconductor. Recently the experimental demonstration of direct band gap emission with hexagonal SiGe alloy, has attracted a strong attention to this material.
The objective of this PhD is to develop a laser based on hexagonal SiGe.
The method to fabricate hexagonal SiGe alloy is based on the epitaxial growth of SiGe on III-V nanowires having wurtzite crystal structure, resulting in epitaxial shell of hexagonal SiGe wrapping the nanowires. Lasing has already been reported in the nanowire geometry for several semiconductors such as GaAs or ZnO . Plasmonic substrates, cavities, or nanowires with a particular geometry are among the most promising approaches to increase the light matter interaction at nanoscale and obtain lasing.
The PhD is divided in three parts.
1. Material growth and characterization using molecular beam epitaxy and electron microscopy.
2. Design and fabrication of the laser using clean room standard tools.
3. Optical Characterizations.
The project will be benefits from the expertise of INL (material growth, structural / optical characterization), and RMIT (device fabrication and characterization). Moreover the involvement of LETI as a non-academic partner will ensure a natural extension of this research towards industry applications.
Option 2
Photodetector based on hexagonal Ge alloy
Infrared photodetectors have attracted considerable research interest over the last years thanks to a wide range of applications in medical imaging, optical communication, security surveillance, and gas identification. Several materials have demonstrated efficient photodetection in the infrared range such as InGaAs, InSb or HgxCd1−xTe. However, the recent experimental demonstration of a direct band gap emission with hexagonal Ge has attracted a strong attention to this material. hexagonal Ge, having a band gap of 0.35 eV, could be used as a mid-IR photodetector and for chemical sensing.
The objective of this PhD is to develop a photodetector based on hexagonal Ge.
The method to fabricate hexagonal Ge is based on the epitaxial growth of Ge on III-V nanowires having wurtzite crystal structure, resulting in epitaxial shell of hexagonal Ge wrapping the nanowires. In order to fabricate a photodetector a particular attention has to be given to the doping.
The PhD is divided in three parts.
1. Material growth and characterization using molecular beam epitaxy and electron microscopy.
2. Design and fabrication of the photodetector using clean room standard tools.
3. Optical and electro-optical characterizations.
The project will be benefits from the expertise of INL (material growth, structural / optical characterization), and RMIT (device fabrication and characterization). Moreover the involvement of LETI will ensure a natural extension of this research to industry applications.
Option 3
Light Emitting diode based on hexagonal SiGe alloy
In the field of silicon photonics, the critical missing device is a monolithic light source completely compatible with complementary-metal-oxide-semiconductor (CMOS) technologies. This is a straightforward consequence of the indirect bandgap of cubic Si semiconductor. Recently the experimental demonstration of direct band gap emission with hexagonal SiGe alloy, has attracted a strong attention to this material.
The objective of this PhD is to develop a light emitting diode based on hexagonal SiGe.
The method to fabricate hexagonal SiGe alloy is based on the epitaxial growth of SiGe on III-V nanowires having wurtzite crystal structure, resulting in epitaxial shell of hexagonal SiGe wrapping the nanowires. A particular attention will be given to the doping of hexagonal SiGe in order to build the PN junction.
The PhD is divided in three parts.
1. Material growth and characterization using molecular beam epitaxy and electron microscopy.
2. Design and fabrication of the laser using clean room standard tools.
3. Optical Characterizations.
The project will be benefits from the expertise of INL (material growth, structural / optical characterization), and RMIT (device fabrication and characterization). Moreover the involvement of LETI will ensure a natural extension of this research to industry applications.
Supervisors
Research Areas
Physics, Material Science, Photonics