Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
The thermal
conductivity of n- and p-type doped
gallium nitride
(GaN) epilayers
having thicknesses of 3–4 μm was investigated using
time domain
thermoreflectance. Despite possessing carrier concentrations ranging
across 3 decades (1015–1018 cm–3), n-type layers exhibit
a nearly constant thermal
conductivity of 180 W/mK. The thermal conductivity of p-type epilayers, in contrast,
reduces from 160 to 110 W/mK with increased doping. These trends—and their overall reduction relative
to bulk—are explained leveraging established scattering models where it is shown that,
while the decrease in p-type layers is partly due to the increased impurity levels evolving from
its doping, size
effects play a primary role in limiting the thermal conductivity of GaN layers tens of microns
thick. Device layers, even of pristine quality, will therefore exhibit thermal conductivities less
than the bulk value of 240 W/mK owing to their finite thickness.