Project Details
Projekt
Growth of ultraclean, isotopically controlled diamond films and nanoparticles with well defined single defects and atomically smooth surfaces
Subject Area
Experimental Condensed Matter Physics
Term
from 2011 to 2022
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 164674487
We intend to develop and to investigate ultra-pure and accordingly custom doped singlecrystalline diamond layers, as well as diamond pin diodes and nanodiamond crystals forapplications in quantum optics using microwave assisted chemical vapor deposition (MWCVD). Single nitrogen-vacancy (NV) and silicon vacancy (SiV) centers will be incorporated either by growth or implantation into diamond pin-diode structures with the aim for electrical stimulated single photon emission. In order to enhance the light output the pin-diodes will be structured into arrays of nanopillars (diameter around 200 nm) using E-beam lithography and ICP etching. For electrical contacting the pillars will be embedded into a SU-8-PDMS matrix (refractive index 1.4 in contrast to diamond with 2.4). On the leveled n-side graphene or indium tin oxide (ITO) will be applied as transparent and conductive contacts, to address the pillars individually. The p-type doped side of the pin-diode will be thinned using RIE and mirror coated, to enhance and direct light emission.Because NV-centers are implanted in many cases near to the surface, the surface Fermi level needs to be fixed to stabilize the charge state of the NV" center. This will be achieved by depositions of a few nanometers thick diamond layers. These thin layers will be doped with phosphorous and nitrogen, at which an optimized doping density will be determined experimentally. In this connection the new MWCVD reactor which was built in the previous project will be of special importance. The new MWCVD-reactor offers the possibility to extract the diamond substrate during epitaxy, thus abrupt, atomically transitions ("delta doping") can be realized by complete exchange of process gases. The new reactor will also be used to deposit ultra-pure diamond layers.As an alternative to ion-implantation we will study the incorporation of rare earth elements in diamond using gas phase doping. This will be done with the objective to identify alternatives to the NV-center in the IR spectral region (>1200 nm). We will apply an in situ gas phase doping approach during CVD-diamond growth using metal organic lanthanide compounds such as tris isopropyl cyclopentadienyl erbium.In contrast to the NV-center, the SiV center exhibits a narrow bandwidth emission. SiV-centers will be incorporated into diamond nanoparticles by MWCVD with the target to use them in photonic structures. In the course of the project, diamond nanoparticles are created from ultra-pure diamond by mechanochemical methods and their geometric properties are specifically optimized by plasma etching. The objective is to remove sharp edges and produce particles between 10 and 50 nm.These particles should be doped with rare earth atoms, SiV and NV centers at lAF. Finally, the spectral characteristics of the emission centers in nano-diamond particles will be stabilized by surface functionalization.
DFG Programme
Research Units
Subproject of
FOR 1493:
Diamond Materials for Quantum Application
Participating Persons
Professor Dr. Oliver Ambacher; Dr. Marco Wolfer
