Optical constants of wurtzite ZnS thin films determined by spectroscopic ellipsometry
Optical constants of wurtzite ZnS thin films determined by spectroscopic ellipsometry
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DOI：
10.1063/1.1419229
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发表时间：
2001-11-26
影响因子：
4
通讯作者：
Chang, RPH
中科院分区：
文献类型：
--
作者：
Ong, HC;Chang, RPH
用椭圆偏振光谱法测量了生长在（0001）Al_2 O_3衬底上的纤锌矿ZnS薄膜在1.33- 4.7eV光谱范围内的复介电函数。在带隙以下，折射率n服从一阶Sellmeir色散关系n（2）（lambda）=1+2.22 lambda（2）/（lambda（2）-0.038（2））。在室温下，清晰地观察到位于带边上方的强且定义明确的自由激子特征。采用修正的Elliott公式和Lorentizan展宽方法拟合了纤锌矿ZnS的吸收光谱，得到了纤锌矿ZnS的带隙和激子结合能等内禀光学参数。这两个参数被发现是大于他们的锌锌的对应物。(C)2001年美国物理学会。
The complex dielectric functions of wurtzite ZnS thin films grown on (0001) Al2O3 have been determined by using spectroscopic ellipsometry over the spectral range of 1.33-4.7 eV. Below the band gap, the refractive index n is found to follow the first-order Sellmeir dispersion relationship n(2)(lambda)=1+2.22 lambda (2)/(lambda (2)-0.038(2)). Strong and well-defined free excitonic features located above the band edge are clearly observed at room temperature. The intrinsic optical parameters of wurtzite ZnS such as band gaps and excitonic binding energies have been determined by fitting the absorption spectrum using a modified Elliott expression together with Lorentizan broadening. Both parameters are found to be larger than their zinc blende counterparts. (C) 2001 American Institute of Physics.