Electrical properties of MOCVD-grown GaN on Si (111) substrates with low-temperature AlN interlayers

The electrical properties of the structure of GaN grown on an Si (111) substrate with low-temperature (LT) AlN interlayers by metal-organic chemical-vapour deposition are investigated. An abnormal P-type conduction is observed in our GaN-on-Si structure by Hall effect measurement, which is mainly due to the Al atom diffusing into the Si substrate and acting as an acceptor dopant. Meanwhile, a constant n-type conduction channel is observed in LT-AlN, which causes a conduction-type conversion at low temperature (50 K) and may further influence the electrical behavior of this structure.