Gallium nitride (GaN) thin film was grown by Nd: YAG pulsed laser ablation with two laser ablation energies. The optical band gaps and crystallinities of the specimens were studied to determine the optimal energy applied. The obtained results ensure that the physical properties of the prepared samples are directly related to the used laser energy. The XRD result exhibited three peaks of hexagonal GAN (h-GaN) nano-particles at 2θ = 34.54°, 37.49° and 48.19 from the (002), (100) and (200) planes, respectively. The ablation energy of 1600 mJ showed a high peak intensity. The samples fabricated at laser energy of 1400 mJ showed the maximum energy bandgap of 3.62 eV at room temperature. High-performance GaN/Si photo-detector was prepared using a drop casting. The spectral response was approximately 2.34 Am/W, and device detectivity was approximately 557.887 × 1012 cm Hz1/2 W−1 in the UV spectral region.
