Photoinduced phenomena in Sr1-xCaxTiO3, 0 ≤ x ≤ 0.12
Photoinduced phenomena in Sr1-xCaxTiO3, 0 ≤ x ≤ 0.12
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Sr1-xCaxTiO3 中的光致现象，0 ≤ x ≤ 0.12
DOI：
10.1080/00150199608224112
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
V. Vikhnin
中科院分区：
文献类型：
--
作者：
S. Basun;U. Bianchi;V. Bursian;A. A. Kaplyanskii;W. Kleemann;P. Markovin;L. S. Sochava;V. Vikhnin
测量了名义纯SrTiO3和铁电Sr1-xCaxTiO3 （x=0.007和0.12）的电导率、Cr3+ r发光、电子顺磁共振、折射率和线性双折射空间变化的光谱、温度和时间变化。在这两种材料中，由于先前的高光子能量照明，发现能量小于2.1 eV的光的光导率都有大的、长时间的持续增加。这一记忆阈值与激发光谱中最强外源带的低能量边缘重合。提出了这两种材料的外在光电过程的基本机理。它们涉及(i)光诱导电荷通过隙内的深能级从价态转移到导带，（ii）由于Cr3+-Cr4+中心的重组，以及（iii）通过相对较浅的陷阱捕获和光诱导发射过程。
Abstract Photoinduced changes of the spectral, temperature and time dependences of the conductivity, the Cr3+ R-luminescence, the electron paramagnetic resonance, the refractive index and of the spatial variation of the linear birefringence are measured in nominally pure SrTiO3 and ferroelectric Sr1-xCaxTiO3 (x=0.007 and 0.12). In both materials a large, long time persisting increase of the photoconductivity for light with energy less than 2.1 eV was found as a result of previous illumination with higher photon energies. This memory threshold coincides with the low energy edge of the strongest extrinsic band in the excitation spectra. Basic mechanisms of extrinsic photoelectronic processes in both materials are proposed. They involve a parallel action of (i) photoinduced charge transfer from the valence to the conduction band via deep energy levels within the gap, (ii) recombination due to Cr3+-Cr4+ centers, and (iii) trapping and light-induced emission processes via relatively shallow traps.