Annealing dependence on flexible p-CuGaO2/n-ZnO heterojunction diode deposited by RF sputtering method Mui Li Lam, Muhammad Hafiz Abu Bakar, Wai Yip Lam, Afishah Alias, Abu Bakar Abd Rahman, Khairul Anuar Mohamad and Katsuhiro Uesugi EPJ Web Conf., 162 (2017) 01061 Published online: 22 November 2017 DOI: 10.1051/epjconf/201716201061