Intense UV emission and lasing action of a single, free-standing and post heat-treated ZnO microribbon - Pangasinan, Jamaica N.; Salazar, Hernanie T.; Salvador, Arnel A.; Sarmago, Roland V.; Arita, Ren; Empizo, Melvin John F.; Yamanoi, Kohei; Minami, Yuki; Shimizu, Toshihiko; Sarukura, Nobuhiko (Proceedings of the 33rd Samahang Pisika ng Pilipinas Physics Congress, 2015)