Electronic transport and band structures of GaAs/AlAs nanostructures superlattices for near-infrared detection

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2017, Vol.123 (1), p.1-7, Article 26
• Main Authors: Barkissy, Driss, Nafidi, Abdelhakim, Boutramine, Abderrazak, Benchtaber, Nassima, Khalal, Ali, El Gouti, Thami
• Format: Article
• Language: English
• Subjects: Advanced Metamaterials and Nanophotonics; Applied physics; Characterization and Evaluation of Materials; Condensed Matter Physics; Machines; Manufacturing; Materials science; Nanotechnology; Optical and Electronic Materials; Physics; Physics and Astronomy; Processes; Superlattices; Surfaces and Interfaces; Thin Films; Valence band
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-016-0629-z

We report here the theoretical calculations of band structures E ( d 1 ), E ( k z , k p ) and effective mass along the growth axis and in the plane of GaAs/Al x Ga 1− x As superlattices, in the envelope function formalism. The effect of valence band offset, well thickness and temperature on the band structures, has been also studied. Our results show that a transition from indirect to direct band gap in (GaAs) m /(AlAs) 4 takes place between m  = 5 and 6 monolayers at room temperature. Samples (GaAs) 9 /(AlAs) 4 and GaAs( d 1  = 10 nm)/Al 0.15 Ga 0.85 As( d 2  = 15 nm) have a direct band gap of 1.747 eV at room temperature and 1.546 eV at T  = 30 mK, respectively. Their corresponding cutoff wavelengths are located in the near infrared region. We have interpreted the photoluminescence measurements of Ledentsov et al. in GaAs( d 1  = 2.52 nm)/AlAs ( d 1  = 1.16 nm) and the oscillations in the magnetoresistance observed by Kawamura et al. in GaAs/Al 0.15 Ga 0.85 As superlattice. In the later, the existence of discrete quantized levels along the growth direction z indicates extremely low interactions between adjacent wells leading to the use in parallel transport. The position of Fermi level predicts that this sample exhibits n-type conductivity. These results were compared and discussed with the available data in the literature and can be used as a guide for the design of infrared nanostructured detectors.