  We study the optical properties of thin flakes of InSe encapsulated in hBN.
More specifically, we investigate the photoluminescence (PL) emission and its
dependence on sample thickness and temperature. Through the analysis of the PL
lineshape, we discuss the relative weights of the exciton and electron-hole
contributions. Thereafter we investigate the PL dynamics. Two contributions are
distinguishable at low temperature: direct bandgap electron-hole and
defect-assisted recombination. The two recombination processes have lifetime of
$\tau_1 \sim 8\;$ns and $\tau_2 \sim 100\;$ns, respectively. The relative
weights of the direct bandgap and defect-assisted contributions show a strong
layer dependence due to the direct-to-indirect bandgap crossover. Electron-hole
PL lifetime is limited by population transfer to lower-energy states and no
dependence on the number of layers was observed. The lifetime of the
defect-assisted recombination gets longer for thinner samples. Finally, we show
that the PL lifetime decreases at high temperatures as a consequence of more
efficient non-radiative recombinations.
