Reduced defect densities in the ZnO epilayer grown on Si substrates by laser-assisted molecular-beam epitaxy using a ZnS epitaxial buffer layer
Reduced defect densities in the ZnO epilayer grown on Si substrates by laser-assisted molecular-beam epitaxy using a ZnS epitaxial buffer layer
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DOI：
10.1063/1.1832734
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发表时间：
2004-12
影响因子：
4
通讯作者：
T. Onuma;S. Chichibu;A. Uedono;Y. Yoo;T. Chikyow;T. Sota;M. Kawasaki;H. Koinuma
中科院分区：
文献类型：
--
作者：
T. Onuma;S. Chichibu;A. Uedono;Y. Yoo;T. Chikyow;T. Sota;M. Kawasaki;H. Koinuma
用激光辅助分子束外延（L-MBE）方法在（111）Si衬底上生长了（0001）ZnO外延层，并以（0001）ZnS外延层为缓冲层，比较了（0001）ZnO外延层与（111）和（001）Si衬底上ZnS外延层热氧化直接转化制备的ZnO薄膜的无辐射光致发光（PL）寿命（τnr）和点缺陷密度。Yoo等人，应用物理信函78，616（2001）]。两种ZnO薄膜在低温下均表现出激子反射率异常和相应的PL峰，单能正电子湮没测量表明，L-MBE外延层中空位型点缺陷（Zn空位）的密度或尺寸低于氧化转变制备的薄膜。在（111）Si衬底上以（0001）ZnS为外延缓冲层生长的ZnO外延层在室温下具有105 ps的较长的τnr。
Nonradiative photoluminescence (PL) lifetime (τnr) and point defect density in the (0001) ZnO epilayer grown on (111) Si substrates by laser-assisted molecular-beam epitaxy (L-MBE) using a (0001) ZnS epitaxial buffer layer were compared with those in the ZnO films on (111) and (001) Si substrates prepared by direct transformation of ZnS epilayers on Si by thermal oxidation [Yoo et al., Appl. Phys. Lett. 78, 616 (2001)]. Both the ZnO films exhibited excitonic reflectance anomalies and corresponding PL peaks at low temperature, and the density or size of vacancy-type point defects (Zn vacancies), which were measured by the monoenergetic positron annihilation measurement, in the L-MBE epilayer was lower than that in the films prepared by the oxidation transformation. The ZnO epilayer grown on a (0001) ZnS epitaxial buffer on (111) Si exhibited longer τnr of 105ps at room temperature.