Bragg reflector and laser fired back contact in a-Si:H/c-Si heterostructure solar cell

M. Tucci, L. Serenelli, E. Salza, L. Pirozzi, G. De Cesare, D. Caputo, M. Ceccarelli

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Abstract

The amorphous/crystalline silicon (a-Si/c-Si) heterostructure has recently attracted new interest due to higher open circuit voltage Vocand low temperature fabrication processes. By reducing the wafer thickness all these characteristics become a necessity, together with the requirement of a back reflecting mirror, to obtain an effective optical confinement. To this aim dielectric mirrors can be adopted in the rear side of the solar cells, together with a local process of laser fired back Al contact. Taking advantage of a-Si/SiNxpassivation properties of c-Si surface a Bragg reflector configuration can be formed on the rear side of the c-Si wafer by Plasma Enhanced Chemical Vapor Deposition (PECVD) alternating several couples of a-Si/SiNxand choosing their thicknesses to maximize the reflectance inward the c-Si wafer in the NIR spectrum. In this work we have adopted this mirror on the rear side of an n-a-Si/i-a-Si/p-c-Si heterostructure solar cell to obtain a full low temperature process. The cell back contact has been ensured by an Al diffusion into the c-Si wafer promoted by Nd-YAG pulsed laser. The front cell contact has been enhanced by chromium silicide CrSi formation on top of the n-a-Si layer and ITO deposition followed by an Ag grid. A Vocof 681 mV and 94% of IQE at 1000 nm have been reached. © 2008 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)48 - 52
Number of pages5
JournalMaterials Science and Engineering B: Solid-State Materials for Advanced Technology
Volume159-160
Issue numberC
DOIs
Publication statusPublished - 15 Mar 2009
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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