Enhanced hole concentration and improved surface morphology for nonpolar a-plane p-type AlGaN/GaN superlattices grown with indium-surfactant

Abstract

Abstract The nonpolar a-plane Mg-delta-doped Al0.6Ga0.4N/GaN superlattices (SLs) with enhanced hole concentration were successfully grown by using indium (In)-surfactant with metal organic chemical vapor deposition (MOCVD) technology. The effect of In-surfactant on the characteristics of the nonpolar a-plane Mg-doped AlGaN/GaN SLs were studied with scanning electron microscopy, atomic force microscopy, X-ray diffraction, and Hall effect measurements. It was found that the surface morphology was improved evidently and the hole concentration was enhanced effectively with the use of In-surfactant. In fact, a root-mean-square value as small as 0.8 nm and a hole concentration as high as 5.1 × 1017 cm-3 were achieved by carefully optimizing the TMIn mole flow rate in the MOCVD growth process. Moreover, it was inferred that the enhancement in hole concentration was due to the significant increase in the Mg incorporation efficiency and the decrease in the self-compensation effect induced by the proper usage of In-surfactant.