Assessment through first-principles calculations of an intermediate-band photovoltaic material based on Ti-implanted silicon: Interstitial versus substitutional origin

K. Sánchez, I. Aguilera, P. Palacios, and P. Wahnón
Phys. Rev. B 79, 165203 – Published 10 April 2009

Abstract

Quantum calculations based on density-functional theory are carried out with the aim of discovering the origin of the electronic properties of Ti-implanted Si. This compound is a potential kind of intermediate-band photovoltaic material. Experimental results show a donor level at a few tenths of an eV below the conduction band for this compound. This could correspond to the electronic transition from an intermediate band to the conduction band of the host silicon. The structural, energetic, and electronic properties of several possible configurations appearing from the implantation of Ti on Si are calculated at different dilution levels in order to agree with the experimental conditions. Among the implantation processes, all of which are energetically unfavorable, interstitial Ti setting implies the energetic balance closest to the equilibrium, which agrees with the experimental measurements. Our conclusions predict that interstitial Ti atoms are responsible for the electronic transition found from the measurements, forecasting that a band fulfilling all the requirements of an intermediate-band material is formed in the compound. The optical absorption coefficient of an interstitially Ti-implanted Si compound is shown to illustrate the photoabsorption enhancement achieved in the main part of the solar spectrum with regard to bulk Si.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
3 More
  • Received 23 December 2008

DOI:https://doi.org/10.1103/PhysRevB.79.165203

©2009 American Physical Society

Authors & Affiliations

K. Sánchez, I. Aguilera, P. Palacios, and P. Wahnón

  • Departamento de Tecnologías Especiales, ETSI Telecomunicación and Instituto de Energía Solar, UPM, Ciudad Universitaria, Madrid 28040, Spain

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 79, Iss. 16 — 15 April 2009

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×