Speaker
Description
Nitride semiconductors became the second most important semiconductor material after
silicon in the last two decades. Many daily used devices, such as blue light emitting diodes or
high electron mobility transistors in electronic devices, are based on nitride semiconductors.
Despite the nitride devices mass production, there are many open questions and not well
understood phenomena which have to be solved.
Epitaxially grown GaN layers contain different bands in their luminescence spectra. There is
very fast excitonic band and also different kinds of defect bands, which have mostly slow
decay time. Fast decay time without any slow components is necessary for many scintillation
applications. Especially defect band with the maximum emission around 2.2 eV (called
yellow band) has very slow decay time (microsecond range) and needs to be suppressed in
fast scintillators.
In our previous work [1], we have shown that different technological parameters during Metal
Organic Vapour Phase Epitaxy (temperature, carrier gas, etc.) influence properties of yellow
band quite significantly. In this work, we continue to study properties of yellow band of GaN
layers grown with different parameters. Photoluminescence, time-resolved photoluminescence
and other measuring techniques are used for investigation of yellow band properties. Origin of
yellow band will be discussed.
[1] T. Hubáček et al., J. Cryst. Growth 531 (2020) 125383.
