OPTICAL ABSORPTION AND PHOTOCONDUCTIVITY IN BAND EDGE OF BETA-GA2O3
OPTICAL ABSORPTION AND PHOTOCONDUCTIVITY IN BAND EDGE OF BETA-GA2O3
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DOI：
10.1103/physrev.140.a316
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发表时间：
1965-01-01
期刊：
影响因子：
--
通讯作者：
TIPPINS, HH
中科院分区：
文献类型：
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作者：
TIPPINS, HH
在名义纯 β− Ga 2 O 3 的单晶中，在紫外光下观察到光吸收和光电导性。在室温下，在 2700 Å 处观察到陡峭的吸收边，这是带间跃迁的特征。当温度降至 77 K 时，边缘向较短波长移动约 100 Å。光电导性在 77 K 时开始与吸收边缘重合，但在室温下无法检测到。提出了一种模型，其中吸收是由于电子从氧 2 p 能带激发到镓 4 s 能带而产生的。使用该模型和玻恩-哈伯循环进行的计算与观察到的带隙 4.7 eV 非常吻合。这表明，与蓝宝石相比，β− Ga 2 O 3 的带隙小得多，这是由于参与跃迁的离子配位数减少所致。
Optical absorption and photoconductivity have been observed in the ultraviolet in single crystals of nominally pure β− Ga 2 O 3. At room temperature a steep absorption edge, characteristic of a band-to-band transition, is observed at 2700 Å. The edge is shifted approximately 100 Å toward shorter wavelengths when the temperature is reduced to 77 K. Photoconductivity begins coincident with the absorption edge at 77 K, but could not be detected at room temperature. A model is proposed in which the absorption arises as a result of excitation of an electron from the oxygen 2 p band to the gallium 4 s band. Calculations using this model and the Born-Haber cycle are in good agreement with the observed band gap of 4.7 eV. It is suggested that the much smaller band gap of β− Ga 2 O 3 as compared with sapphire is due to the reduced coordination number of the ions involved in the transition.