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Title: Rectification and tunneling effects enabled by Al{sub 2}O{sub 3} atomic layer deposited on back contact of CdTe solar cells

Atomic layer deposition (ALD) of Aluminum oxide (Al{sub 2}O{sub 3}) is employed to optimize the back contact of thin film CdTe solar cells. Al{sub 2}O{sub 3} layers with a thickness of 0.5 nm to 5 nm are tested, and an improved efficiency, up to 12.1%, is found with the 1 nm Al{sub 2}O{sub 3} deposition, compared with the efficiency of 10.7% without Al{sub 2}O{sub 3} modification. The performance improvement stems from the surface modification that optimizes the rectification and tunneling of back contact. The current-voltage analysis indicates that the back contact with 1 nm Al{sub 2}O{sub 3} maintains large tunneling leakage current and improves the filled factor of CdTe cells through the rectification effect. XPS and capacitance-voltage electrical measurement analysis show that the ALD-Al{sub 2}O{sub 3} modification layer features a desired low-density of interface state of 8 × 10{sup 10 }cm{sup −2} by estimation.
Authors:
; ; ; ; ; ; ; ; ;  [1]
  1. School of Advanced Materials, Peking University Shenzhen Graduate School, Peking University, Shenzhen 518055 (China)
Publication Date:
OSTI Identifier:
22483167
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALUMINIUM OXIDES; CADMIUM TELLURIDES; CAPACITANCE; DEPOSITION; EFFICIENCY; ELECTRIC POTENTIAL; INTERFACES; LAYERS; LEAKAGE CURRENT; MODIFICATIONS; SOLAR CELLS; SURFACES; THICKNESS; THIN FILMS; TUNNEL EFFECT; X-RAY PHOTOELECTRON SPECTROSCOPY