Farbzentren im Kristall : NV(Stickstoff-Fehlstellen)-Zentren in hochreinen Diamant-Einkristallen
Mit der Frage nach Kristallgitterverunreinigungen im Diamanten beschäftigt sich dieser Text. Diese sogenannten NV-Zentren haben ein enormes Potenzial für Anwendungen wie Biosensoren für die Medizintechnik oder Quantencomputer.
Photons from ideal single-photon
sources exhibit quantum mechanical
characteristics and are therefore
suited to applications in novel fields,
including quantum cryptography
and spintronics. However, the biggest
challenge for the implementation
of this concept is maintaining the
coherence of the quantum states for
a sufficiently long time. One promising
candidate for this task is the
nitrogen-vacancy center in diamond.
The N-V center is a point defect in
diamond and one of its properties is
strong photoluminescence, which can
be detected spectroscopically. The
electron spins at N-V centers can be
manipulated at room temperature
by applying magnetic or electric
fields, microwave radiation or light,
or a combination of these, resulting
in sharp resonances in the intensity
and wavelength of the photoluminescence.
An individual N-V center
can thus be viewed as a very sensitive
sensor for these effects. The main aim of this project is
the fabrication and investigation of
near-surface N-V centers in highpurity
single-crystal diamond films.
Preparation of these active elements
close to the surface with good properties
is a task which has not yet
been sufficiently accomplished, especially
when read-out is desired to be
performed using both optical and
electronical means. In this project
the influence of diamond properties,
as well as the structure and termination
of the diamond surface at the
spin centers, is investigated. Pure
single-crystal diamond films are
homoepitaxially grown by microwave
plasma-assisted chemical vapor
deposition and the film quality is
characterized by standard methods.
N-V centers are produced by ion
implantation and properties of these
are spectroscopically investigated.