The refractive index in the photon energy range between 1 and 5.5 eV and temperatures between 7 and 295 K was deduced from the interference fringes. $$, $$ n(E)={\left[a{\left(\frac{E}{E_g}\right)}^2\left(2-{\left(1+\frac{E}{E_g}\right)}^{0.5}-{\left(1-\frac{E}{E_g}\right)}^{0.5}\right)+b\right]}^{0.5} $$, Nanoscale strain field around dislocations, http://creativecommons.org/licenses/by/4.0/, https://doi.org/10.1186/s11671-019-3018-7. Free online database of refractive index values, with material optical constants listed versus wavelength for Thin Film Thickness Measurement Birefringence of GaN/AlGaN optical waveguides. 0000010182 00000 n The photoelastic constants matrix P of wurtzite AlN is shown as expression (4) [29, 30]. 0000021263 00000 n X.}". The total thickness of AlN film is about 1.1 μm. Modeling the optical constants of AlN and 6H-SiC. The results showed that periodicity of 60° was found for the birefringence change versus the waveguide orientation. 0000011275 00000 n After 15-min high-temperature AlN growth, an AlN interlayer was grown at 1050 °C for 160 s. Finally, the growth temperature was raised to 1280 °C to grow thick HT AlN for 50 min. Together they form a unique fingerprint. The confining potential in the heterostructures is assumed to be semiparabolic. Cite this article. note = "Copyright: Copyright 2008 Elsevier B.V., All rights reserved.". %PDF-1.3 %���� 0000007630 00000 n J Appl Phys 103:123112, Hall D, Bacon DJ (2001) Introduction to dislocations. β is the FWHM of XRC. Thin Solid Films 158:L39–L43, Ghosha S, Piazza G (2016) Laterally vibrating resonator based elasto-optic modulation in aluminum nitride. Part of Therefore, revealing the factors that affect the refractive index of AlN is important.It can be learned from previous studies that the refractive index of AlN can be affected by many factors including temperature, pressure, and bandgap. 0000014578 00000 n 0000002666 00000 n Based on the calculation, the distributions of refractive index (take the refractive index at 633 nm as an example) around unit screw and unit edge dislocations are shown in Fig. 0000003542 00000 n Figure S5. Taken the matrices (7) and (8) into formula (3), we can get the expression of Δn caused by unit screw and unit edge dislocation. Proceedings Volume 4283, Physics and Simulation of Optoelectronic Devices IX; A strained InGaAs InAlAs coupled quantum well with polarization independent... Franz Keldysh effect and exciton ionization in a short one... Quasi-symmetric coupled quantum well and its electro-optical properties. 0000002688 00000 n Revealing the dependence of the refractive index of AlN on the threading dislocations is meaningful since high-density threading dislocations usually exist in AlN. AB - A study was performed on birefringence of GaN/AlGaN planar optical waveguides grown on a sapphire substrate. This work was supported by the National Key R&D Program of China (2017YFB0404103). Therefore, the change of TDDs plays a key role in the change of the refractive index of AlN. Superlattice Microst 104:240–246, CAS Revealing the dependence of the refractive index of AlN on the threading dislocations is meaningful since high-density threading dislocations usually exist in AlN. It was demonstrated that the refractive index not only depends on the signal polarization states parallel or perpendicular to the c axis, it also depends on the direction of optical propagation in the a-b plane. On the one hand, higher refractive-index contrast will be obtained with a lower Al content in the AlGaN layer, resulting in a high-reflectivity DBR. It was demonstrated that the refractive index not only depends on the signal polarization states parallel or perpendicular to the c axis, it also depends on the direction of optical propagation in the a-b plane. Aleksandra B. Djurisic, Y. Chan, E. Herbert Li, "Calculations of the refractive index of AlGaN/GaN quantum well," Proc. The results showed that periodicity of 60° was found for the birefringence change versus the waveguide orientation.". 0000007357 00000 n It means that the dislocations in AlN make the refractive index smaller than that of bulk AlN crystal. By continuing you agree to the use of cookies. We have calculated the refractive index of a Al x Ga 1-x N/GaN square quantum well (QW). However, with the increase of compressive stress, the refractive index becomes closer to that of bulk AlN at 633 nm. Appl Phys Lett 88:061904, Du J, An Y, Zhang C, Zhu C, Li X, Ma D (2019) Photonic design and electrical evaluation of dual-functional solar cells for energy conversion and display applications. The distribution of refractive index at 633 nm around a unit screw dislocation and b unit edge dislocation. To access this item, please sign in to your personal account. 0000004111 00000 n Compared with AlGaAs/GaAs heterostructures and quantum dots, the amount of the refractive index is larger in the AlGaN/GaN quantum well heterostructures studied. 0000004016 00000 n Simulated results reveal that the refractive index changes strongly depend on both the Al composition and the delta-doping concentration.
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