Structure and energy gap of Cd1−xCaxTe and Cd1−yCaySe as a function of Ca2+ incorporation
Structure and energy gap of Cd1−xCaxTe and Cd1−yCaySe as a function of Ca2+ incorporation
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Cd1−xCaxTe 和 Cd1−yCaySe 的结构和能隙随 Ca2+ 掺入的变化
DOI：
10.1088/0268-1242/20/2/014
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发表时间：
2005
影响因子：
1.9
通讯作者：
S. Miotkowska
中科院分区：
文献类型：
--
作者：
I. Miotkowski;H. Alawadhi;M. Seong;S. Tsoi;A. Ramdas;S. Miotkowska
用布里奇曼技术生长的Cd1−xCaxTe和Cd1−yCaySe三元单晶，通过微探针和x射线技术表征，显示x和y的上限为0.05。激子的能隙，确定从自由激子的波长调制反射率的衍生签名，显示出线性增加，在两个三元合金中的Ca2+浓度的增加。在光致发光中观察到的施主束缚和受主束缚激子的近带隙发射，作为合金组合物的函数进行研究，揭示施主束缚激子签名的蓝移，与观察到的自由激子的蓝移一致。Cd1−xCaxTe的拉曼光谱显示出明显的类CaTe LO声子的存在，证实了Ca的掺入确实导致了具有特征双模行为的三元Cd1−xCaxTe。
Single crystals of Cd1−xCaxTe and Cd1−yCaySe ternaries, grown by the Bridgman technique and characterized by microprobe and x-ray techniques, showed the upper limit of x and y to be 0.05. The excitonic energy gap, determined from the derivative signature of free excitons in wavelength modulated reflectivity, shows a linear increase with increasing Ca2+ concentration in both ternary alloys. The near-band gap emissions of donor-bound and of acceptor-bound excitons observed in photoluminescence, investigated as a function of alloy composition, reveal blue shifts of donor-bound excitonic signatures, in good agreement with those observed for free excitons. The Raman spectra of Cd1−xCaxTe reveal the clear presence of CaTe-like LO phonons, confirming that the Ca incorporation has indeed resulted in a ternary Cd1−xCaxTe with a characteristic two-mode behaviour.