Valence band control of ZnO and fabrication of p-n junction for light emitting device

利用激光MBE实现了ZnO薄膜在原子平面蓝宝石（0001）衬底上的外延生长，并对其面内取向和表面极性进行了控制[1]。Ohkubo等人，冲浪。科学。左443，L1043(1999)]。制备出质量可与化合物半导体相媲美的高品质ZnO/MgZnO超晶格，并观察到量子效应引起的能隙蓝移[A]。Ohtomo等人，苹果公司。理论物理。左，75,980 (1999)；[j].科学通报，1999(5)。通常，价带控制对薄膜的质量要求很高，我们尝试用ScAlMgO4衬底来制作更高质量的薄膜，ScAlMgO4衬底与ZnO的晶格匹配非常好。结果制备出了与单晶相当的高质量ZnO薄膜[a]。Ohtomo等人，苹果公司。理论物理。《社会科学》第7卷第2期[j]。激子发光性能提高[T]。Makino等人，苹果公司。理论物理。此外，还观察到了高质量ZnO/MgZnO和CdZnO/MgZnO超晶格的室温激子发光[j]。牧野等着。,达成。理论物理。Lett. 77, 975 (2000)；[7]；sun等人，苹果公司。理论物理。[j].科学通报，2004,(2)。此外，ZnO/MgZnO超晶格在室温下产生激子的受激发射[A]。Ohtomo等人，苹果公司。理论物理。《社会科学》，2002年第1期[j]。p型ZnO的制备尚未完成，但ZnO薄膜的能带工程得到了很大的发展。

Epitaxial growth of ZnO thin film on atomically flat sapphire (0001) substrate was achieved by using laser MBE, in addition, control of in-plane orientation and surface polarity were done [I.Ohkubo et al., Surf. Sci. Lett. 443, L1043 (1999)]. High grade ZnO/MgZnO superlattice was made, whose quality was comparable to that of compound semiconductors, and the blue-shift of energy gap due to the quantum effect was observed [A.Ohtomo et al., Appl. Phys. Lett, 75, 980 (1999) ; 75, 4088 (1999)]. Generally, valence band control needs high quality of thin film, we tried to made higher quality thin film, by using ScAlMgO4 substrate, lattice matching of which with ZnO was very good. As a result, very high quality ZnO thin film comparable to single crystal was made [A.Ohtomo et al., Appl. Phys. Lett. 75, 2635 (1999)]. The exciton luminescence properties was increased [T.Makino et al., Appl. Phys. Lett. 76, 3549 (2000)], Also, the room temperature exciton luminescences of high quality ZnO/MgZnO and CdZnO/MgZnO superlattices were observed [T.Makino et at., Appl. Phys. Lett. 77, 975 (2000) ; 77, 1632 (2000) ; H.D.Sun et al., Appl. Phys. Lett. 77, 4250 (2000)]. Further, ZnO/MgZnO superlattice generated stimulated emission of exciton at room temperature [A.Ohtomo et al., Appl. Phys. Lett. 77, 2204 (2000)]. Fabrication of p-type ZnO has not been done, but band engineering of ZnO thin film was greatly developed.