Polymorph-Selective Deposition of High Purity SnS Thin Films from a Single Source Precursor

Research output: Contribution to journalArticle

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Abstract

Metal chalcogenide thin films have a wide variety of applications and potential uses. Tin(II) Sulfide, is one such materi-al which presents a significant challenge with the need for high quality SnS, free of oxide materials (e.g. SnO2) oxides and higher tin sulfides (e.g. Sn2S3 and SnS2). This problem is compounded further when the target material exhibits a number of polymorphic forms with different optoelectronic properties. Unlike conventional chemical vapor deposition (CVD) and atomic layer deposition (ALD), which relies heavily on having precursors that are volatile, stable and reac-tive, the use of aerosol assisted CVD (AA-CVD) negates the need for volatile precursors. We report here, for the first time, the novel and structurally characterized single source precursor (1), Dimethylamido-(N-Phenyl-N’,N’-Dimethyl-Thiouriate)Sn(II) dimer, and its application in the deposition, by AA-CVD, of phase-pure films of SnS. A mechanism for the oxidatively controlled formation of SnS from precursor (1) is also reported. Significantly, thermal control of the deposition process allows for the unprecedented selective and exclusive formation of either orthorhombic-SnS (α-SnS) or zinc blende-SnS (ZB-SnS) polymorphs. Thin films of α-SnS or ZB-SnS have been deposited onto Mo, FTO, Si and glass substrates at the optimized deposition temperatures of 375 oC and 300 oC, respectively. The densely packed poly-crystalline thin films have been characterized by XRD, SEM, AFM, Raman spectroscopy, EDS and XPS analysis. These data confirmed the phase purity of the SnS formed. Optical analysis of the α-SnS and ZB-SnS films show distinctly dif-ferent optical properties with direct band gaps of 1.34 eV and 1.78 eV, respectively. Furthermore photoelectrochemical and external quantum efficiency (EQE) measurements were undertaken to assess the optoelectronic properties of the deposited samples. We also report for the first time the ambipolar properties of the ZB-SnS phase.
LanguageEnglish
Pages7680-7688
JournalChemistry of Materials
Volume27
Issue number22
Early online date15 Oct 2015
DOIs
StatusPublished - 24 Nov 2015

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Polymorphism
Zinc
Chemical vapor deposition
Thin films
Aerosols
Optoelectronic devices
Oxides
Tin
Atomic layer deposition
Sulfides
Quantum efficiency
Dimers
Raman spectroscopy
Energy dispersive spectroscopy
Energy gap
X ray photoelectron spectroscopy
Optical properties
Metals
Crystalline materials
Glass

Keywords

  • Thin Films
  • CVD
  • Polymorphism
  • Photoelectrochemistry
  • Tin Monosulfide
  • Photovoltaics

Cite this

Polymorph-Selective Deposition of High Purity SnS Thin Films from a Single Source Precursor. / Johnson, Andrew L.; Ahmet, Ibby Y.; Hill, Michael S.; Peter, Laurence M.

In: Chemistry of Materials, Vol. 27, No. 22, 24.11.2015, p. 7680-7688.

Research output: Contribution to journalArticle

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title = "Polymorph-Selective Deposition of High Purity SnS Thin Films from a Single Source Precursor",
abstract = "Metal chalcogenide thin films have a wide variety of applications and potential uses. Tin(II) Sulfide, is one such materi-al which presents a significant challenge with the need for high quality SnS, free of oxide materials (e.g. SnO2) oxides and higher tin sulfides (e.g. Sn2S3 and SnS2). This problem is compounded further when the target material exhibits a number of polymorphic forms with different optoelectronic properties. Unlike conventional chemical vapor deposition (CVD) and atomic layer deposition (ALD), which relies heavily on having precursors that are volatile, stable and reac-tive, the use of aerosol assisted CVD (AA-CVD) negates the need for volatile precursors. We report here, for the first time, the novel and structurally characterized single source precursor (1), Dimethylamido-(N-Phenyl-N’,N’-Dimethyl-Thiouriate)Sn(II) dimer, and its application in the deposition, by AA-CVD, of phase-pure films of SnS. A mechanism for the oxidatively controlled formation of SnS from precursor (1) is also reported. Significantly, thermal control of the deposition process allows for the unprecedented selective and exclusive formation of either orthorhombic-SnS (α-SnS) or zinc blende-SnS (ZB-SnS) polymorphs. Thin films of α-SnS or ZB-SnS have been deposited onto Mo, FTO, Si and glass substrates at the optimized deposition temperatures of 375 oC and 300 oC, respectively. The densely packed poly-crystalline thin films have been characterized by XRD, SEM, AFM, Raman spectroscopy, EDS and XPS analysis. These data confirmed the phase purity of the SnS formed. Optical analysis of the α-SnS and ZB-SnS films show distinctly dif-ferent optical properties with direct band gaps of 1.34 eV and 1.78 eV, respectively. Furthermore photoelectrochemical and external quantum efficiency (EQE) measurements were undertaken to assess the optoelectronic properties of the deposited samples. We also report for the first time the ambipolar properties of the ZB-SnS phase.",
keywords = "Thin Films, CVD, Polymorphism, Photoelectrochemistry, Tin Monosulfide, Photovoltaics",
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T1 - Polymorph-Selective Deposition of High Purity SnS Thin Films from a Single Source Precursor

AU - Johnson,Andrew L.

AU - Ahmet,Ibby Y.

AU - Hill,Michael S.

AU - Peter,Laurence M.

PY - 2015/11/24

Y1 - 2015/11/24

N2 - Metal chalcogenide thin films have a wide variety of applications and potential uses. Tin(II) Sulfide, is one such materi-al which presents a significant challenge with the need for high quality SnS, free of oxide materials (e.g. SnO2) oxides and higher tin sulfides (e.g. Sn2S3 and SnS2). This problem is compounded further when the target material exhibits a number of polymorphic forms with different optoelectronic properties. Unlike conventional chemical vapor deposition (CVD) and atomic layer deposition (ALD), which relies heavily on having precursors that are volatile, stable and reac-tive, the use of aerosol assisted CVD (AA-CVD) negates the need for volatile precursors. We report here, for the first time, the novel and structurally characterized single source precursor (1), Dimethylamido-(N-Phenyl-N’,N’-Dimethyl-Thiouriate)Sn(II) dimer, and its application in the deposition, by AA-CVD, of phase-pure films of SnS. A mechanism for the oxidatively controlled formation of SnS from precursor (1) is also reported. Significantly, thermal control of the deposition process allows for the unprecedented selective and exclusive formation of either orthorhombic-SnS (α-SnS) or zinc blende-SnS (ZB-SnS) polymorphs. Thin films of α-SnS or ZB-SnS have been deposited onto Mo, FTO, Si and glass substrates at the optimized deposition temperatures of 375 oC and 300 oC, respectively. The densely packed poly-crystalline thin films have been characterized by XRD, SEM, AFM, Raman spectroscopy, EDS and XPS analysis. These data confirmed the phase purity of the SnS formed. Optical analysis of the α-SnS and ZB-SnS films show distinctly dif-ferent optical properties with direct band gaps of 1.34 eV and 1.78 eV, respectively. Furthermore photoelectrochemical and external quantum efficiency (EQE) measurements were undertaken to assess the optoelectronic properties of the deposited samples. We also report for the first time the ambipolar properties of the ZB-SnS phase.

AB - Metal chalcogenide thin films have a wide variety of applications and potential uses. Tin(II) Sulfide, is one such materi-al which presents a significant challenge with the need for high quality SnS, free of oxide materials (e.g. SnO2) oxides and higher tin sulfides (e.g. Sn2S3 and SnS2). This problem is compounded further when the target material exhibits a number of polymorphic forms with different optoelectronic properties. Unlike conventional chemical vapor deposition (CVD) and atomic layer deposition (ALD), which relies heavily on having precursors that are volatile, stable and reac-tive, the use of aerosol assisted CVD (AA-CVD) negates the need for volatile precursors. We report here, for the first time, the novel and structurally characterized single source precursor (1), Dimethylamido-(N-Phenyl-N’,N’-Dimethyl-Thiouriate)Sn(II) dimer, and its application in the deposition, by AA-CVD, of phase-pure films of SnS. A mechanism for the oxidatively controlled formation of SnS from precursor (1) is also reported. Significantly, thermal control of the deposition process allows for the unprecedented selective and exclusive formation of either orthorhombic-SnS (α-SnS) or zinc blende-SnS (ZB-SnS) polymorphs. Thin films of α-SnS or ZB-SnS have been deposited onto Mo, FTO, Si and glass substrates at the optimized deposition temperatures of 375 oC and 300 oC, respectively. The densely packed poly-crystalline thin films have been characterized by XRD, SEM, AFM, Raman spectroscopy, EDS and XPS analysis. These data confirmed the phase purity of the SnS formed. Optical analysis of the α-SnS and ZB-SnS films show distinctly dif-ferent optical properties with direct band gaps of 1.34 eV and 1.78 eV, respectively. Furthermore photoelectrochemical and external quantum efficiency (EQE) measurements were undertaken to assess the optoelectronic properties of the deposited samples. We also report for the first time the ambipolar properties of the ZB-SnS phase.

KW - Thin Films

KW - CVD

KW - Polymorphism

KW - Photoelectrochemistry

KW - Tin Monosulfide

KW - Photovoltaics

UR - http://dx.doi.org/10.1021/acs.chemmater.5b03220

U2 - 10.1021/acs.chemmater.5b03220

DO - 10.1021/acs.chemmater.5b03220

M3 - Article

VL - 27

SP - 7680

EP - 7688

JO - Chemistry of Materials

T2 - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 22

ER -