# Time resolved Photoluminescence analysis

1. ### ezimah

2
Currently we are working on gallium nitride material where I'm required to analyze the time resolved photoluminescence (PL) result. From literature review we found that many reported on lifetime decay value $\tau$ so could anyone explain how to find this value. Does it come from the time resolved PL slope or there any specific equation we need to uses?

2. ### Cthugha

1,715
GaN has a direct band gap, so one usually just assumes that the decay of the signal is an exponential decay and the decay constant is the lifetime decay value. What may happen is that there are several possible decay channels, for example radiative and nonradiative ones. In that case one would expect a multi-exponential decay showing more than one time scale. However, this is usually already quite easy to spot in a log plot of the decay.

The other thing you might want or need to worry about is the detection. It may make a difference whether you have a detector integrating over the whole emission spectrum or a spectrally resolving one as the PL spectrum may change over the PL duration. Usually doing both is fine as long as you mention what you actually measured.

3. ### ezimah

2
Thank for the reply.it's help me a lot.