Temperature-dependent optical properties of hexagonal and cubic MgxZn1-xO thin-film alloys
Temperature-dependent optical properties of hexagonal and cubic MgxZn1-xO thin-film alloys
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六方晶系和立方晶系 MgxZn1-xO 薄膜合金的温度相关光学特性
DOI：
10.1088/0953-8984/16/17/024
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发表时间：
2004-05-05
影响因子：
2.7
通讯作者：
Shen, WZ
中科院分区：
文献类型：
--
作者：
Chen, NB;Wu, HZ;Shen, WZ
在c面（0001）蓝宝石衬底上低温生长了六方和立方MgxZn1-xO（0 ≤ x ≤ 0.6）薄膜。X射线衍射分析表明，立方相MgxZn1-xO薄膜沿沿着[111]方向生长，而六方相ZnO薄膜沿沿着[0001]方向生长。利用紫外光透射法测量了MgxZn1-xO薄膜在10~300 K温度范围内的光学性质，并对吸收光谱进行了理论拟合。对于0 <x ≤ 0.51的MgxZn（1-x）O，只观察到稳定的六方相，且光吸收边随温度的升高单调红移。对于x ≥ 0.55的MgxZn1-xO，在300 K时晶体结构为立方结构。然而，当测量温度从300 K降低到10 K时，观察到光学吸收的异常，这归因于可能的从立方结构到六方结构的相变。晶体相变的基本物理机制是由于应力与立方MgxZn 1-xO中的层错的相互作用。
Both hexagonal and cubic MgxZn1-xO (0 less than or equal to x less than or equal to 0.6) films were grown on c-plane (0001) sapphire substrate at low temperature. X-ray diffraction measurements show that the cubic MgxZn1-xO films grow along the [111] direction while the hexagonal ZnO films grow along [0001]. The temperature-dependent optical properties of MgxZn1-xO films were measured by ultraviolet optical transmission with temperature variation from 10 to 300 K and analysed by theoretically fitting the optical absorption spectra. For MgxZn1-xO with 0 < x less than or equal to 0.51, only stable hexagonal phase was observed and the optical absorption edge red shifts with temperature increase monotonically. For MgxZn1-xO with x greater than or equal to 0.55, the crystal structure is cubic at 300 K. However, as measurement temperature decreases from 300 to 10 K an abnormality of the optical absorption is observed, which is attributed to the possible phase transition from cubic to hexagonal structure. The underlying physical mechanism for the crystal phase transition is attributed to the interaction of stress with stacking faults in the cubic MgxZn1-xO.