Low leakage Mg-compensated GaN Schottky diodes on free-standing GaN substrate for high energy $\alpha$-particle detection

Low leakage current Schottky barrier diodes (SBDs) were fabricated on $\mathbf{30}\ \mu\mathbf{m}$ thick Mg-compensated GaN drift layer (DL) grown on a free-standing GaN substrate and tested up to 5.48 MeV $\alpha$ -particle energy. The Mg-compensated $\mathbf{30}\ \mu\mathbf{m}$ thick n--GaN DL was grown by MOCVD with low charge carrier density (CCD) of $\mathbf{4.1}\times \mathbf{10}^{\mathbf{15}}/\mathbf{cm}^{\mathbf{3}}$ . The observation of low CCD in the GaN DL by Mg-compensation helps to reduce the reverse leakage current (I R ) of SBDs to 2 pA and in the formation of $\mathbf{30}\mu\mathbf{m}$ depletion width (DW) even at 0 V. The fabricated GaN SBDs detected $\alpha$ -particle up to energy of 5.48 MeV with high charge collection efficiencies (CCE) of 100% emitted from ²⁴¹ Am source.