  In this report, we demonstrate dual band vertical heterojunction
photodetector realized by integrating {\alpha}-In2Se3 with p-type GaN. Flakes
of ~ 110 nm thickness were exfoliated on MOCVD grown p-GaN on silicon
substrate. Devices showed two distinct detection peaks in spectral
responsivity, one at 365 nm and another at 850 nm, corresponding to band edges
of GaN and {\alpha}-In2Se3 respectively, with considerable rejection in visible
spectrum. Normalised responsivity values were found out to be ~70 mA/W at both
365 nm and 850 nm for the bias of -3V along with photo-to-dark current ratio of
~665 and ~75 in that order. The Devices also showed fast transient response
with no persistent photoconductivity (PPC). The specific detectivity values
estimated were ~10^11 Jones and ~10^10 Jones corresponding to illumination at
365 nm and 850 nm respectively. A good linearity of ~0.4 was observed in power
dependent analysis of spectral responsivity at 365 nm. The device performance,
post annealing was also studied. This study is expected to pave way for new
type of optoelectronic devices by integrating direct bandgap layered material
like {\alpha}-In2Se3 and wide bandgap semiconductors.
