Intermediate Band to Conduction Band optical absorption in ZnTe:O

Antolín Fernández, Elisa and Chen, C. and Ramiro Gonzalez, Iñigo and Foley, James and López Estrada, Esther and Artacho Huertas, Irene and Hwang, J. and Teran, A. and Hernández Martín, Estela and Tablero Crespo, César and Martí Vega, Antonio and Phillips, J.D. and Luque López, Antonio (2012). Intermediate Band to Conduction Band optical absorption in ZnTe:O. In: "38th IEEE Photovoltaic Specialists Conference (PVSC), 2012", 03/06/2012 - 08/06/2012, Austin, Texas (EEUU).

Description

Title: Intermediate Band to Conduction Band optical absorption in ZnTe:O
Author/s:
  • Antolín Fernández, Elisa
  • Chen, C.
  • Ramiro Gonzalez, Iñigo
  • Foley, James
  • López Estrada, Esther
  • Artacho Huertas, Irene
  • Hwang, J.
  • Teran, A.
  • Hernández Martín, Estela
  • Tablero Crespo, César
  • Martí Vega, Antonio
  • Phillips, J.D.
  • Luque López, Antonio
Item Type: Presentation at Congress or Conference (Article)
Event Title: 38th IEEE Photovoltaic Specialists Conference (PVSC), 2012
Event Dates: 03/06/2012 - 08/06/2012
Event Location: Austin, Texas (EEUU)
Title of Book: 38th IEEE Photovoltaic Specialists Conference (PVSC), 2012
Date: June 2012
Subjects:
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Electrónica Física
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

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.

More information

Item ID: 20735
DC Identifier: http://oa.upm.es/20735/
OAI Identifier: oai:oa.upm.es:20735
Deposited by: Memoria Investigacion
Deposited on: 09 Oct 2013 18:12
Last Modified: 22 Sep 2014 11:21
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