skip to main content

Title: Amorphous silicon enhanced metal-insulator-semiconductor contacts for silicon solar cells

Carrier recombination at the metal-semiconductor contacts has become a significant obstacle to the further advancement of high-efficiency diffused-junction silicon solar cells. This paper provides the proof-of-concept of a procedure to reduce contact recombination by means of enhanced metal-insulator-semiconductor (MIS) structures. Lightly diffused n{sup +} and p{sup +} surfaces are passivated with SiO{sub 2}/a-Si:H and Al{sub 2}O{sub 3}/a-Si:H stacks, respectively, before the MIS contacts are formed by a thermally activated alloying process between the a-Si:H layer and an overlying aluminum film. Transmission/scanning transmission electron microscopy (TEM/STEM) and energy dispersive x-ray spectroscopy are used to ascertain the nature of the alloy. Idealized solar cell simulations reveal that MIS(n{sup +}) contacts, with SiO{sub 2} thicknesses of ∼1.55 nm, achieve the best carrier-selectivity producing a contact resistivity ρ{sub c} of ∼3 mΩ cm{sup 2} and a recombination current density J{sub 0c} of ∼40 fA/cm{sup 2}. These characteristics are shown to be stable at temperatures up to 350 °C. The MIS(p{sup +}) contacts fail to achieve equivalent results both in terms of thermal stability and contact characteristics but may still offer advantages over directly metallized contacts in terms of manufacturing simplicity.
Authors:
; ;  [1] ; ; ;  [2]
  1. Research School of Engineering, The Australian National University, Canberra, ACT 0200 (Australia)
  2. Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Micro Engineering (IMT), Photovoltaics and Thin Film Electronic Laboratory PVLab, Maladière 71b, CH-200 Neuchâtel (Switzerland)
Publication Date:
OSTI Identifier:
22308156
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALLOYS; ALUMINIUM OXIDES; AMORPHOUS STATE; CURRENT DENSITY; FILMS; HYDROGENATION; LAYERS; MIS SOLAR CELLS; RECOMBINATION; SEMICONDUCTOR JUNCTIONS; SEMICONDUCTOR MATERIALS; SILICON; SILICON OXIDES; SILICON SOLAR CELLS; SIMULATION; SURFACES; TRANSMISSION; TRANSMISSION ELECTRON MICROSCOPY; X-RAY SPECTROSCOPY