Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/101914
Title: Effects of Ar+ etching of Cu2ZnSnSe4 thin films: An x-ray photoelectron spectroscopy and photoluminescence study
Authors: Yakushev, M. V.
Sulimov, M. A.
Skidchenko, E.
Márquez-Prieto, J.
Forbes, I.
Edwards, P. R.
Kuznetsov, M. V.
Zhivulko, V. D.
Borodavchenko, O. M.
Mudryi, A. V.
Krustok, J.
Martin, R. W.
Issue Date: 2018
Publisher: AVS Science and Technology Society
Citation: Effects of Ar+ etching of Cu2ZnSnSe4 thin films: An x-ray photoelectron spectroscopy and photoluminescence study / M. V. Yakushev, M. A. Sulimov, E. Skidchenko, et al. — DOI 10.1116/1.5050243 // Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics. — 2018. — Vol. 36. — Iss. 6. — 061208.
Abstract: Cu2ZnSnSe4 (CZTSe) is a semiconductor used as the absorber layer in highly promising sustainable thin film solar cells. The authors study the effect of Ar+ etching of copper deficient and zinc excess CZTSe thin films deposited on Mo/glass substrates on the surface elemental composition, measured by x-ray photoelectron spectroscopy, and photoluminescence (PL) spectra. Low temperature PL spectra reveal a broad asymmetrical band at 0.95 eV. The temperature and excitation intensity dependencies of this band suggest that it is a free-to-bound (FB) recombination of electrons from the conduction band with holes localized at an acceptor affected by potential fluctuations. The surface composition of the as grown films demonstrates a strong copper deficiency: [Cu]/[Zn + Sn] = 0.33. The etching of the film surface using Ar+ beam increases [Cu]/[Zn + Sn] to 0.51, which is significantly smaller than that of 0.78 in the bulk, measured by wavelength dispersive x-ray analysis, demonstrating the presence on the surface of a copper-depleted layer. The Ar+ etching drastically reduces the FB band intensity by a factor of 4.5, broadens it and develops a low energy tail. Ar ions displace atoms in CZTSe lattice creating primary radiation defects, vacancies, and interstitials, which recombine at room temperature forming antisite defects with deep energy levels. Some of them generate the observed low energy tail and increase the mean depth of potential fluctuation γ, determined from the shape of the low energy side of FB band, from 24 meV before Ar+ etching to 35 meV after. Other deep defects work as nonradiative recombination centers reducing the intensity of the FB band. © 2018 Author(s).
Keywords: COPPER
COPPER COMPOUNDS
ENERGY DISPERSIVE X RAY ANALYSIS
ETCHING
PHOTOELECTRONS
PHOTOLUMINESCENCE
PHOTONS
SELENIUM COMPOUNDS
SEMICONDUCTING TIN COMPOUNDS
SEMICONDUCTING ZINC COMPOUNDS
TEMPERATURE
THIN FILM SOLAR CELLS
THIN FILMS
TIN COMPOUNDS
X RAY DIFFRACTION ANALYSIS
X RAY PHOTOELECTRON SPECTROSCOPY
DEEP ENERGY LEVELS
EXCITATION INTENSITY
NONRADIATIVE RECOMBINATION CENTERS
PHOTOLUMINESCENCE SPECTRUM
POTENTIAL FLUCTUATIONS
PRIMARY RADIATIONS
SURFACE ELEMENTAL COMPOSITIONS
WAVELENGTH DISPERSIVE X-RAYS
SEMICONDUCTING SELENIUM COMPOUNDS
URI: http://hdl.handle.net/10995/101914
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85056265830
PURE ID: 8332270
9bdc125a-9b33-46c5-896a-04781f2275a8
ISSN: 21662746
DOI: 10.1116/1.5050243
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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