Application of the transition semiconductor semimetal in modulated nanostructures for communication as infrared optoelectronic device

• Published in: Physica. B, Condensed matter Condensed matter, 2010-02, Vol.405 (3), p.936-940
• Main Authors: El Abidi, A., Nafidi, A., Chaib, H., El Kaaouachi, A., Braigue, M., Morghi, R., EL Yakoubi, E.Y., d’Astuto, M.
• Format: Article
• Language: English
• Subjects: Band structure; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in multilayers, nanoscale materials and structures; Envelope function formalism; Exact sciences and technology; Magneto-transport measurements; Medium-infrared detector HgTe/CdTe superlattices; Narrow gap nano-semiconductor; Physics; Superlattices; Two-dimensional electronic system
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2009.10.019

We report here electronic properties of a two-dimensional modulated superlattice nanostructure. Our sample, grown by MBE, had a period d= d 1+ d 2 (90 layers) of d 1=5.6 nm (HgTe)/ d 2=3 nm (CdTe). Calculations of the specters of energy E( d 2), E( k z ) and E( k p), respectively, in the direction of growth and in plane of the superlattice; were performed in the envelope function formalism. The energy E ( d 2, Γ, 4.2 K,), shown that for each d 1/ d 2, when d 2 increase the gap E g decrease to zero at the transition semiconductor to semimetal conductivity behavior and become negative accusing a semimetallic conduction. At 4.2 K, the sample exhibits p type conductivity with a Hall mobility of 8200 cm 2/Vs. This allowed us to observe the Shubnikov-de Haas effect with p=1.80×10 12 cm −2. Using the calculated effective mass ( m HH * = 0 , 297 m 0 ) of the degenerated heavy holes gas, the Fermi energy (2D) was E F=14 meV in agreement with 12 meV of thermoelectric power α. In intrinsic regime, α∼ T −3/2 and R H T 3/2 indicates a gap E g= E 1− HH 1=190 meV in agreement with calculated E g ( Γ, 300 K)=178 meV. The formalism used here predicts that this sample is a narrow gap, two-dimensional modulated nanostructure and medium-infrared detector.