Observatorio de I+D+i UPM

Memorias de investigación
Intermediate-Band to Conduction-Band optical absorption in ZnTeO
Research Areas
  • Electric engineers, electronic and automatic (eil),
  • Electronic devices,
  • Solar cells,
  • Technology of devices for engineering
ZnTe doped with high concentrations of oxygen has been proposed in previous works as intermediate band (IB) material for photovoltaic applications. The existence of extra optical transitions related to the presence of an IB has already been demonstrated in this material and it has been possible to measure the absorption coefficient of the transitions from the valence band (VB) to the IB. In this work we present the first measurement of the absorption coefficient associated to transitions from the IB to the conduction band (CB) in ZnTe:O. The samples used are 4 ?m thick ZnTe layers with or without O in a concentration ~ 1019 cm-3, which have been grown on semi-insulating GaAs substrates by molecular beam epitaxy (MBE). The IB-CB absorption coefficient peaks for photon energies ~ 0.4 eV. It is extracted from reflectance and transmittance spectra measured using Fourier Transform Infrared (FTIR) spectroscopy. Under typical FTIR measurement conditions (low light intensity, broadband spectrum) the absorption coefficient in IB-to-CB transitions reaches 700 cm-1. This is much weaker than the one observed for VB-IB absorption. This result is consistent with the fact that the IB is expected to be nearly empty of electrons under equilibrium conditions in ZnTe(:O). The absorption for VB to IB transitions is also observed in the same samples through reflectance measurements performed in the visible range using a monochromator. These measurements are compared with the quantum efficiency (QE) from solar cells fabricated under similar conditions.
IEEE (38th IEEE Photovoltaic Specialists Conference)
Entity Nationality
Austin, Texas (EEUU)
  • Autor: Elisa Antolin Fernandez (UPM)
  • Autor: C. Chen
  • Autor: Iñigo Ramiro Gonzalez (UPM)
  • Autor: J. Foley
  • Autor: Esther Lopez Estrada (UPM)
  • Autor: Irene Artacho Huertas (UPM)
  • Autor: J. Hwang
  • Autor: A. Teran
  • Autor: Estela Hernandez Martin (UPM)
  • Autor: Cesar Tablero Crespo (UPM)
  • Autor: Antonio Marti Vega (UPM)
  • Autor: J.D. Phillips
  • Autor: Antonio Luque Lopez (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Silicio y Nuevos Conceptos para Células Solares
  • Centro o Instituto I+D+i: Instituto de Energía Solar
  • Departamento: Electrónica Física
S2i 2020 Observatorio de investigación @ UPM con la colaboración del Consejo Social UPM
Cofinanciación del MINECO en el marco del Programa INNCIDE 2011 (OTR-2011-0236)
Cofinanciación del MINECO en el marco del Programa INNPACTO (IPT-020000-2010-22)