Speaker
Description
Semiconductor detectors for ionizing radiation (X- and gamma-rays,
electrons, protons, alpha particles, heavy ions) are employed
extensively for spectrometry, dosimetry and imaging in many fields:
from fundamental scientific research to medical applications, homeland
security, material analysis and industrial applications. Many of these
applications have increasingly demanding requirements on the detector
devices, including high energy resolution, low power consumption,
low-noise room temperature operation, structural stability, and
radiation hardness to name only a few.
It is clear that the Si-based device technology of today cannot
meet these criteria. This creates a desperate need for novel
semiconductor materials, innovative device designs and advanced
manufacturing processes across many applications.
A noticeable trend in functional materials is to turn towards 2D
materials. A very promising concept are detectors based on silicon
carbide/graphene. Compared to everyday silicon, silicon carbide (SiC)
has lower noise levels at room temperature. Furthermore, it is
intrinsically more resistant to radiation damage due to its
stronger-bound cristal lattice. This physical strength of SiC also
allows for ultra-thin membrane detectors that can be used in special
applications such as living cell radiology and even intelligent
vacuum windows. By depositing graphene layers into etched structures
on the SiC, a monolithic material which combines the
radiation resistance of SiC with the high electron conductivity of
graphene may be created.
Further, SiC offers exciting possibilities in a field where the
applications of semiconductor detectors are essentially unexplored:
the detection of neutrons. Being uncharged, neutrons are detected only
indirectly, e.g. via nuclear reactions in a converter material (for
low-energy or "thermal" neutrons) or via recoil reactions (for
high-energy or fast neutrons). In SiC, neutrons recoiling from the
carbon nucleus yield a very distinct signature. By depositing
moderator or converter materials such as polyethylene or 10B into
structures on the SiC, this sensitivity can be increased and extended
to thermal neutrons.
Thin, low-noise, radiation-hard, and mechanically stable
semiconductor detectors capable of detecting a wide energy-range of
neutrons as well as ionizing radiation are clearly invaluable for
future scientific instruments, whether it is the final instrumentation
suite of ESS or the next-generation of tracking detectors in particle
physics experiments. With the existing experience and infrastructure for semiconductor
development and neutron detection, and the established and ongoing
collaboration with ESS and industrial partners of ACREO and
Graphensic, the Physics Department at Lund University is
the place where SiC can be established as the go-to semiconductor
technology of 2025 in science.
