CdTe Thin Films from Nanoparticle Precursors by Spray Deposition

Douglas L. Schulz; Martin Pehnt; Doug H. Rose; Ed Urgiles; Andrew F. Cahill; David W. Niles; Kim M. Jones; Randy J. Ellingson; Calvin J. Curtis; David S. Ginley

doi:10.1021/cm9601547

CdTe Thin Films from Nanoparticle Precursors by Spray Deposition

Douglas L. Schulz
, Martin Pehnt
, Doug H. Rose
, Ed Urgiles
, Andrew F. Cahill
, David W. Niles
, Kim M. Jones
, Randy J. Ellingson
, Calvin J. Curtis
, David S. Ginley

Materials, Chemical, and Computational Science

National Renewable Energy Laboratory

Research output: Contribution to journal › Article › peer-review

29 Scopus Citations

Abstract

The formation of CdTe thin films by spray deposition using nanoparticle colloids has been investigated. Employing a metathesis approach, cadmium iodide is reacted with sodium telluride in methanol solvent, resulting in the formation of soluble NaI and insoluble CdTe nanoparticles. After appropriate chemical workup, methanol-capped CdTe colloids were isolated. CdTe colloids prepared by this method exhibit a dependence of the nanoparticle diameter upon reaction temperature as determined by UV-visible spectroscopy (UV-vis), X-ray diffraction (XRD), and transmission electron microscopy (TEM). CdTe thin-film formation was performed by spray depositing the 25-75 Å diameter nanoparticle colloids according to a one- or two-step method. Films derived from a one-step approach were sprayed onto substrates at elevated temperatures (T_dep = 280-440°C) with no further thermal treatment. Two-step films were sprayed at lower temperatures (T_dep = 25-125°C) and were subjected to subsequent thermal treatments (T_anneal = 250-500°C) in argon or forming gas (10% H₂ in N₂) ambients. The effects of a CdCl₂ treatment were also investigated for CdTe films on both 7059 glass and CdS on SnO₂-coated 7059 glass. The CdTe films were characterized by XRD, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Phase-pure cubic CdTe formation was observed by XRD for two-step derived films (400°C in forming gas) while one-step films were composed of the cubic CdTe and an oxide phase. XPS analysis of five films processed at 400°C and a variety of conditions showed that while CdTe films produced by the one-step method contained no Na or C and substantial O, two-step films subjected to a CdCl₂ treatment showed reduced O but increased C content. AFM gave CdTe grain sizes of ∼0.1-0.3 and ∼0.3-0.7 μm for a one-step film sprayed at 400°C and a two-step film annealed at 400°C, respectively. The potential of employing CdTe nanoparticles toward photovoltaic technologies is discussed.

Original language	American English
Pages (from-to)	889-900
Number of pages	12
Journal	Chemistry of Materials
Volume	9
Issue number	4
DOIs	https://doi.org/10.1021/cm9601547 https://doi.org/10.1021/cm9601547
State	Published - 1997

NLR Publication Number

NREL/JA-520-23346

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@article{e2854a21321543c19a9ae23616c30871,

title = "CdTe Thin Films from Nanoparticle Precursors by Spray Deposition",

abstract = "The formation of CdTe thin films by spray deposition using nanoparticle colloids has been investigated. Employing a metathesis approach, cadmium iodide is reacted with sodium telluride in methanol solvent, resulting in the formation of soluble NaI and insoluble CdTe nanoparticles. After appropriate chemical workup, methanol-capped CdTe colloids were isolated. CdTe colloids prepared by this method exhibit a dependence of the nanoparticle diameter upon reaction temperature as determined by UV-visible spectroscopy (UV-vis), X-ray diffraction (XRD), and transmission electron microscopy (TEM). CdTe thin-film formation was performed by spray depositing the 25-75 {\AA} diameter nanoparticle colloids according to a one- or two-step method. Films derived from a one-step approach were sprayed onto substrates at elevated temperatures (Tdep = 280-440°C) with no further thermal treatment. Two-step films were sprayed at lower temperatures (Tdep = 25-125°C) and were subjected to subsequent thermal treatments (Tanneal = 250-500°C) in argon or forming gas (10\% H2 in N2) ambients. The effects of a CdCl2 treatment were also investigated for CdTe films on both 7059 glass and CdS on SnO2-coated 7059 glass. The CdTe films were characterized by XRD, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Phase-pure cubic CdTe formation was observed by XRD for two-step derived films (400°C in forming gas) while one-step films were composed of the cubic CdTe and an oxide phase. XPS analysis of five films processed at 400°C and a variety of conditions showed that while CdTe films produced by the one-step method contained no Na or C and substantial O, two-step films subjected to a CdCl2 treatment showed reduced O but increased C content. AFM gave CdTe grain sizes of ∼0.1-0.3 and ∼0.3-0.7 μm for a one-step film sprayed at 400°C and a two-step film annealed at 400°C, respectively. The potential of employing CdTe nanoparticles toward photovoltaic technologies is discussed.",

author = "Schulz, \{Douglas L.\} and Martin Pehnt and Rose, \{Doug H.\} and Ed Urgiles and Cahill, \{Andrew F.\} and Niles, \{David W.\} and Jones, \{Kim M.\} and Ellingson, \{Randy J.\} and Curtis, \{Calvin J.\} and Ginley, \{David S.\}",

year = "1997",

doi = "10.1021/cm9601547",

language = "American English",

volume = "9",

pages = "889--900",

journal = "Chemistry of Materials",

issn = "0897-4756",

publisher = "American Chemical Society",

number = "4",

}

TY - JOUR

T1 - CdTe Thin Films from Nanoparticle Precursors by Spray Deposition

AU - Schulz, Douglas L.

AU - Pehnt, Martin

AU - Rose, Doug H.

AU - Urgiles, Ed

AU - Cahill, Andrew F.

AU - Niles, David W.

AU - Jones, Kim M.

AU - Ellingson, Randy J.

AU - Curtis, Calvin J.

AU - Ginley, David S.

PY - 1997

Y1 - 1997

N2 - The formation of CdTe thin films by spray deposition using nanoparticle colloids has been investigated. Employing a metathesis approach, cadmium iodide is reacted with sodium telluride in methanol solvent, resulting in the formation of soluble NaI and insoluble CdTe nanoparticles. After appropriate chemical workup, methanol-capped CdTe colloids were isolated. CdTe colloids prepared by this method exhibit a dependence of the nanoparticle diameter upon reaction temperature as determined by UV-visible spectroscopy (UV-vis), X-ray diffraction (XRD), and transmission electron microscopy (TEM). CdTe thin-film formation was performed by spray depositing the 25-75 Å diameter nanoparticle colloids according to a one- or two-step method. Films derived from a one-step approach were sprayed onto substrates at elevated temperatures (Tdep = 280-440°C) with no further thermal treatment. Two-step films were sprayed at lower temperatures (Tdep = 25-125°C) and were subjected to subsequent thermal treatments (Tanneal = 250-500°C) in argon or forming gas (10% H2 in N2) ambients. The effects of a CdCl2 treatment were also investigated for CdTe films on both 7059 glass and CdS on SnO2-coated 7059 glass. The CdTe films were characterized by XRD, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Phase-pure cubic CdTe formation was observed by XRD for two-step derived films (400°C in forming gas) while one-step films were composed of the cubic CdTe and an oxide phase. XPS analysis of five films processed at 400°C and a variety of conditions showed that while CdTe films produced by the one-step method contained no Na or C and substantial O, two-step films subjected to a CdCl2 treatment showed reduced O but increased C content. AFM gave CdTe grain sizes of ∼0.1-0.3 and ∼0.3-0.7 μm for a one-step film sprayed at 400°C and a two-step film annealed at 400°C, respectively. The potential of employing CdTe nanoparticles toward photovoltaic technologies is discussed.

AB - The formation of CdTe thin films by spray deposition using nanoparticle colloids has been investigated. Employing a metathesis approach, cadmium iodide is reacted with sodium telluride in methanol solvent, resulting in the formation of soluble NaI and insoluble CdTe nanoparticles. After appropriate chemical workup, methanol-capped CdTe colloids were isolated. CdTe colloids prepared by this method exhibit a dependence of the nanoparticle diameter upon reaction temperature as determined by UV-visible spectroscopy (UV-vis), X-ray diffraction (XRD), and transmission electron microscopy (TEM). CdTe thin-film formation was performed by spray depositing the 25-75 Å diameter nanoparticle colloids according to a one- or two-step method. Films derived from a one-step approach were sprayed onto substrates at elevated temperatures (Tdep = 280-440°C) with no further thermal treatment. Two-step films were sprayed at lower temperatures (Tdep = 25-125°C) and were subjected to subsequent thermal treatments (Tanneal = 250-500°C) in argon or forming gas (10% H2 in N2) ambients. The effects of a CdCl2 treatment were also investigated for CdTe films on both 7059 glass and CdS on SnO2-coated 7059 glass. The CdTe films were characterized by XRD, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Phase-pure cubic CdTe formation was observed by XRD for two-step derived films (400°C in forming gas) while one-step films were composed of the cubic CdTe and an oxide phase. XPS analysis of five films processed at 400°C and a variety of conditions showed that while CdTe films produced by the one-step method contained no Na or C and substantial O, two-step films subjected to a CdCl2 treatment showed reduced O but increased C content. AFM gave CdTe grain sizes of ∼0.1-0.3 and ∼0.3-0.7 μm for a one-step film sprayed at 400°C and a two-step film annealed at 400°C, respectively. The potential of employing CdTe nanoparticles toward photovoltaic technologies is discussed.

UR - https://www.scopus.com/pages/publications/0001438092

U2 - 10.1021/cm9601547

DO - 10.1021/cm9601547

M3 - Article

AN - SCOPUS:0001438092

SN - 0897-4756

VL - 9

SP - 889

EP - 900

JO - Chemistry of Materials

JF - Chemistry of Materials

IS - 4

ER -

CdTe Thin Films from Nanoparticle Precursors by Spray Deposition

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