This study presents a simulation of the optical absorption spectra within the THz frequency region using Matlab, considering a doping concentration of N=1×1040 cm−3. Quantum well (QW) widths of 25 nm, 30 nm, 35 nm, and 40 nm were analyzed, with results depicted in Figures 11 through 14, respectively. The simulations incorporate varying dephasing energies Γ of 8 meV, 12 meV, and 16 meV to account for broadening mechanisms such as phonon interactions, impurity scattering, and other dephasing processes. A clear redshift in the absorption edge is observed with increasing QW width, as evidenced in results, indicating that wider wells accommodate lower energy confinement states. Additionally, the absorption peaks become sharper as the QW width increases, consistent. The dephasing energy significantly influences the spectral line shape; higher Γ values result in broader absorption features with diminished peak intensity, reflecting increased scattering and reduced electronic coherence. Conversely, lower Γ (8 meV) yields sharper peaks, aligning with previous experimental research by scholars. These results underscore the critical role of QW dimensions and dephasing mechanisms in tailoring the optical properties of quantum wells, which is essential for optimizing THz optoelectronic devices.

Adamu, S. B., Adamu, S. B., Faragai, I. A., & Ibrahim, U. (2019). Optical Absorption in GaAs/AlGaAs Quantum Well due to Intersubband transitions. Alb Albo A., Fekete, D., & Bahir, G. (2012). Electronic bound states in the continuum above (Ga,In)(As,N)/(Al,Ga)As quantum wells. Physical Review B - Condensed Matter and Materials Physics, 85(11). https://doi.org/10.1103/PhysRevB.85.115307 J. Zhang, H. Liu, and X. W. (2021). Effects of Quantum Well Width and Temperature on the Optical Absorption Spectra of GaAs/AlGaAs Quantum Wells. Materials, 14(19), 2345. Jr, M. F. P., &Faragai, I. A. (2014). Coupling of THz radiation with intervalence band transitions in microcavities. 22(3), 3439–3446. https://doi.org/10.1364/OE.22.003439 L. Zhang, Y. Chen, and M. W. (2022). Dephasing mechanismsin semiconductor quantum wells: A review of experimental and theoretical advances. Journal of Applied Physics, 131(12), 12090. Liu, S., Han, Q., Luo, W., Lei, W., Zhao, J., Wang, J., Jiang, Y., & Raschke, M. B. (2024). Recent progress of innovative infrared avalanche photodetectors. Infrared Physics & Technology, 105114. https://doi.org/10.1016/j.infrared.2023.105114 Pereira, M. F., & Faragai, I. A. (2013). THz Intervalence Band Polaritons and Antipolaritons. 13–15. Redaelli, L., Mukhtarova, A., Ajay, A., Núñez-Cascajero, A., Valdueza-Felip, S., Bleuse, J., Durand, C., Eymery, J., & Monroy, E. (2015). Effect of the barrier thickness on the performance of multiple-quantum-well InGaN photovoltaic cells. Japanese Journal of Applied Physics, 54(7). https://doi.org/10.7567/JJAP.54.072302 Unuma, T., Yoshita, M., Noda, T., Sakaki, H., & Akiyama, H. (2003). Intersubband absorption linewidth in GaAs quantum wells due to scattering by interface roughness, phonons, alloy disorder, and impurities. Journal of Applied Physics, 93(3), 1586–1597. https://doi.org/10.1063/1.1535733 Wu, C. H., Ku, C. J., Yu, M. W., Yang, J. H., Wu, P. Y., Huang, C. Bin, Lu, T. C., Huang, J. S., Ishii, S., & Chen, K. P. (2023). Near-Field Photodetection in Direction Tunable Surface Plasmon Polaritons Waveguides Embedded with Graphene. Advanced Science, 10(30). https://doi.org/10.1002/advs.202302707 Wu, M. C. (n.d.). EE 232 Lightwave Devices Lecture 9: Intersubband Absorption i Q t W ll in Quantum Wells. Zhang, G., Xu, C., Sun, D., Wang, Q., Lu, G., & Gong, Q. (2024). Metasurface-tuned light-matter interactions for high-performance photodetectors. Fundamental Research. https://doi.org/10.1016/j.fmre.2024.01.002