Role of the defect microstructure on the electrical transport properties in undoped and Si-doped GaN grown by LP-MOVPE

Abstract

Experimental results show that the room-temperature carrier mobility in bulk layers of undoped or Si-doped GaN grown by LP-MOVPE on sapphire substrate shows a sudden increase as soon as the carrier density exceeds a critical value of about 1018 cm-3. We show that such a behavior can be theoretically reproduced by assuming that the columnar structure (i.e. the dislocation microstructure) is responsible for internal electronic barriers.