Abstract
Recently it was shown a new approach based on
all-semiconductor material technology which is
composed with a near ultra-violet GaN LED excitation
source and fluorescent silicon carbide (f-6H-SiC)
substrate which generates a visible broad spectral light
by N and B dopants and an efficient donor to acceptor
pair recombination [1,2]. This combination can achieve
higher electric-light conversion efficiency and high
color rendering in comparison with today’s used blue
GaN LED based and phosphors. The devices are
promising candidates for general lightning applications
and may obtain stability/reproducibility, and potentially
low cost in high performance LEDs. However, there are
still many problems to obtain best optimization for
f-6H-SiC material since neither carrier transport, nor the
carrier recombination is known in such co-doped
carbides. From the existing data of carrier lifetimes in
the SiC materials it is impossible to calculate
requirements for epilayer thicknesses, for surfaces and
interfaces that can provide sink for non-intentional
losses of emission probability.
In this work we report on carrier lifetime studies in
f-6H-SiC epitaxial growth layers that are co-doped by N
and B impurities. Epitaxial samples were grown by a
sublimation growth process using a control of source
materials. Variable concentration of B and N dopants
was uniform over epitaxial thicknesses 45-60 m as was
obtained by SIMS measurements (Table 1). Samples
had different PL intensity at 300 K.
Free-carrier-absorption technique under co-linear and
orthogonal probe geometry was used to measure carrier
lifetimes in the layers under variable injection
conditions. Same results are shown in Fig. 1
exaggerating the fact that longer electron lifetime responsible for higher emission and
n-type doping should prevail the p-type doping in active
layer of 6H-SiC. An appropriate model for explaining
experimental findings will be presented together with an
appropriate model for the LED device.
Original language | English |
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Publication date | 2011 |
Publication status | Published - 2011 |
Event | 39th Lithuanian National Physics Conference - Vilnius, Lithuania Duration: 6 Oct 2011 → 8 Oct 2011 Conference number: 39 |
Conference
Conference | 39th Lithuanian National Physics Conference |
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Number | 39 |
Country/Territory | Lithuania |
City | Vilnius |
Period | 06/10/2011 → 08/10/2011 |