Absorption Coefficient and Refractive Index of GaN, AlN and AlGaN Alloys
Absorption Coefficient and Refractive Index of GaN, AlN and AlGaN Alloys
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DOI：
10.1557/s1092578300002957
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
J. Muth;J. Brown;Mark L. Johnson;Z. Yu;R. Kolbas;J. Cook;J. Schetzina
中科院分区：
文献类型：
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作者：
J. Muth;J. Brown;Mark L. Johnson;Z. Yu;R. Kolbas;J. Cook;J. Schetzina
由III族氮化物材料制造的光电子器件的设计由这些材料的折射率和吸收系数的知识辅助。通过透射率和反射率的测量，研究了蓝宝石衬底上MOVPE生长的GaN、AlN和AlGaN的光学特性。薄（小于0.5 μm）的单晶薄膜，以确保传输测量可以获得远高于光学带隙。通过一系列Al组分的AlGaN合金样品，研究了合金展宽对吸收边的影响。对于具有高达38%Al组合物的AlGaN，获得了带隙以上的光吸收系数。对于相同系列的样品，测定带隙以下的折射率。这些特性为日盲探测器或其他光电器件的优化设计提供了关键信息。
The design of optoelectronic devices fabricated from III-nitride materials is aided by knowledge of the refractive index and absorption coefficient of these materials. The optical properties of GaN, AlN and AlGaN grown by MOVPE on sapphire substrates were investigated by means of transmittance and reflectance measurements. Thin (less than 0.5 μm) single crystal films were employed to insure that transmission measurements could be obtained well above the optical band gap. The influence of alloy broadening on the absorption edge was investigated by using a series of AlGaN alloy samples with a range of Al compositions. The optical absorption coefficient above the band gap was obtained for AlGaN having up to 38% Al composition. The refractive index below the band gap was determined for the same series of samples. These properties provide information critical to the optimal design of solar blind detectors or other optoelectronic devices.