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Title: Amorphous silicon passivated contacts for diffused junction silicon solar cells

Carrier recombination at the metal contacts is a major obstacle in the development of high-performance crystalline silicon homojunction solar cells. To address this issue, we insert thin intrinsic hydrogenated amorphous silicon [a-Si:H(i)] passivating films between the dopant-diffused silicon surface and aluminum contacts. We find that with increasing a-Si:H(i) interlayer thickness (from 0 to 16 nm) the recombination loss at metal-contacted phosphorus (n{sup +}) and boron (p{sup +}) diffused surfaces decreases by factors of ∼25 and ∼10, respectively. Conversely, the contact resistivity increases in both cases before saturating to still acceptable values of ∼ 50 mΩ cm{sup 2} for n{sup +} and ∼100 mΩ cm{sup 2} for p{sup +} surfaces. Carrier transport towards the contacts likely occurs by a combination of carrier tunneling and aluminum spiking through the a-Si:H(i) layer, as supported by scanning transmission electron microscopy–energy dispersive x-ray maps. We explain the superior contact selectivity obtained on n{sup +} surfaces by more favorable band offsets and capture cross section ratios of recombination centers at the c-Si/a-Si:H(i) interface.
Authors:
; ; ;  [1] ; ; ;  [2]
  1. Research School of Engineering, The Australian National University, Canberra, ACT 0200 (Australia)
  2. École Polytechnique Fédérale de Lausanne (EPFL), Institute of micro engineering (IMT), Photovoltaics and Thin Film Electronic Laboratory, Maladière 71, CH-200 Neuchâtel (Switzerland)
Publication Date:
OSTI Identifier:
22273513
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; 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; ALUMINIUM; BORON; CHARGE CARRIERS; CROSS SECTIONS; HETEROJUNCTIONS; HYDROGENATION; INTERFACES; LAYERS; RECOMBINATION; SILICON; SILICON SOLAR CELLS; SURFACES; TUNNEL EFFECT