Optical properties of hexagonal boron nitride
Optical properties of hexagonal boron nitride
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DOI：
10.1103/physrevb.13.5560
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发表时间：
1976-06
影响因子：
3.7
通讯作者：
A. Zunger;A. Katzir;A. Halperin
中科院分区：
文献类型：
--
作者：
A. Zunger;A. Katzir;A. Halperin
测量了六方氮化硼薄膜在近紫外波段（1950-3200 \AA{}）的光吸收、反射率和光电导。在6.2eV处观察到主吸收峰。在约5.8 eV处的急剧下降归因于直接带隙。发现带隙的温度依赖性小于4 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}5}$ eV/\ifmmode^\circ\else\textdegree\fi{}K。采用半经验LCAO（linear combination of atomic orbitals）方法计算哈密顿矩阵元，在二维六方晶体模型上进行了自洽紧束缚能带结构计算.六方BN的带隙的计算值是在合理的良好协议与本工作中获得的实验值，以及与早期报道的电子能量损失和光电子发射测量值。计算还预测了带隙随温度的变化非常小，与实验观察结果一致。
Optical absorption, reflectivity, and photoconductivity in the near-uv range (1950-3200 \AA{}) of a thin film of hexagonal boron nitride were measured. The main absorption peak was observed at 6.2 eV. A sharp fall at about 5.8 eV was attributed to the direct band gap. The temperature dependence of the band gap was found to be less than 4 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}5}$ eV/\ifmmode^\circ\else\textdegree\fi{}K. Self-consistent tight-binding band-structure calculations were performed on a two-dimensional hexagonal crystal model, using Hamiltonian matrix elements calculated by semiempirical LCAO (linear combination of atomic orbitals) methods. The calculated value for the band gap of hexagonal BN was in reasonably good agreement with the experimental value obtained in the present work, as well as with values reported earlier from electron-energy-loss and photoelectron-emission measurements. The calculations also predicted a very small change in the band gap with temperature, in agreement with the experimental observations.