Effect of an Al-adlayer in the c-plane ZnO/AlN heterostructure Dongmei Bai, Hao Liu, Aixia Zhang, Jianli Wang, Gang Tang, Junting Zhang and C. Stampfl EPL, 122 2 (2018) 26003 Published online: 19 June 2018 DOI: 10.1209/0295-5075/122/26003