Effect of TMAl flow rate on AlInGaN/GaN heterostructures grown by MOCVD

In this work, lattice-matched AlInGaN/GaN epilayers are grown on c-plane Al2O3 substrate by metal organic chemical vapor deposition technique. The structural and optical properties of AlInGaN/GaN epilayers have been studied and compared. TMIn and TMAl flow is believed to have a direct impact on the quality of AlInGaN epilayer. By varying In and Al composition in AlInGaN epilayer, dislocations (V-pit density) have been found to decrease, indicating lower threading dislocation density as confirmed by HRXRD and AFM. Reciprocal space mapping analysis has confirmed that the growth of AlInGaN on GaN buffer is a fully lattice matched growth. AlInGaN exhibits two emissions originating from In(Ga)N clusters and the AlInGaN random matrix is confirmed by photoluminescence. In the Raman spectra of AlInGaN, A1 (LO) mode at 751 cm−1 and In(Ga)N clustering A1(LO) mode at 680 cm−1 is observed. These findings open the new advancement in the field of opto-electronic applications.