Impact of annealing on the chemical structure and morphology of the thin-film CdTe/ZnO interface

K. Horsley, R. J. Beal, R. G. Wilks, M. Blum, M. Häming, D. A. Hanks, M. G. Weir, T. Hofmann, L. Weinhardt, M. Bär, Barrett G Potter, C. Heske

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

To enable an understanding and optimization of the optoelectronic behavior of CdTe-ZnO nanocomposites, the morphological and chemical properties of annealed CdTe/ZnO interface structures were studied. For that purpose, CdTe layers of varying thickness (4-24nm) were sputter-deposited on 100nm-thick ZnO films on surface-oxidized Si(100) substrates. The morphological and chemical effects of annealing at 525°C were investigated using X-ray Photoelectron Spectroscopy (XPS), X-ray-excited Auger electron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, and atomic force microscopy. We find a decrease of the Cd and Te surface concentration after annealing, parallel to an increase in Zn and O signals. While the as-deposited film surfaces show small grains (100nm diameter) of CdTe on the ZnO surface, annealing induces a significant growth of these grains and separation into islands (with diameters as large as 1μm). The compositional change at the surface is more pronounced for Cd than for Te, as evidenced using component peak fitting of the Cd and Te 3d XPS peaks. The modified Auger parameters of Cd and Te are also calculated to further elucidate the local chemical environment before and after annealing. Together, these results suggest the formation of tellurium and cadmium oxide species at the CdTe/ZnO interface upon annealing, which can create a barrier for charge carrier transport, and might allow for a deliberate modification of interface properties with suitably chosen thermal treatment parameters.

Original languageEnglish (US)
Article number024312
JournalJournal of Applied Physics
Volume116
Issue number2
DOIs
StatePublished - Jul 14 2014

Fingerprint

annealing
thin films
x rays
photoelectron spectroscopy
chemical effects
tellurium
chemical properties
cadmium
Auger spectroscopy
thick films
electron spectroscopy
charge carriers
nanocomposites
atomic force microscopy
scanning electron microscopy
optimization
oxides
spectroscopy
energy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Horsley, K., Beal, R. J., Wilks, R. G., Blum, M., Häming, M., Hanks, D. A., ... Heske, C. (2014). Impact of annealing on the chemical structure and morphology of the thin-film CdTe/ZnO interface. Journal of Applied Physics, 116(2), [024312]. https://doi.org/10.1063/1.4890235

Impact of annealing on the chemical structure and morphology of the thin-film CdTe/ZnO interface. / Horsley, K.; Beal, R. J.; Wilks, R. G.; Blum, M.; Häming, M.; Hanks, D. A.; Weir, M. G.; Hofmann, T.; Weinhardt, L.; Bär, M.; Potter, Barrett G; Heske, C.

In: Journal of Applied Physics, Vol. 116, No. 2, 024312, 14.07.2014.

Research output: Contribution to journalArticle

Horsley, K, Beal, RJ, Wilks, RG, Blum, M, Häming, M, Hanks, DA, Weir, MG, Hofmann, T, Weinhardt, L, Bär, M, Potter, BG & Heske, C 2014, 'Impact of annealing on the chemical structure and morphology of the thin-film CdTe/ZnO interface', Journal of Applied Physics, vol. 116, no. 2, 024312. https://doi.org/10.1063/1.4890235
Horsley, K. ; Beal, R. J. ; Wilks, R. G. ; Blum, M. ; Häming, M. ; Hanks, D. A. ; Weir, M. G. ; Hofmann, T. ; Weinhardt, L. ; Bär, M. ; Potter, Barrett G ; Heske, C. / Impact of annealing on the chemical structure and morphology of the thin-film CdTe/ZnO interface. In: Journal of Applied Physics. 2014 ; Vol. 116, No. 2.
@article{29f07c7e90d947e6a55f5a9d3ef891b9,
title = "Impact of annealing on the chemical structure and morphology of the thin-film CdTe/ZnO interface",
abstract = "To enable an understanding and optimization of the optoelectronic behavior of CdTe-ZnO nanocomposites, the morphological and chemical properties of annealed CdTe/ZnO interface structures were studied. For that purpose, CdTe layers of varying thickness (4-24nm) were sputter-deposited on 100nm-thick ZnO films on surface-oxidized Si(100) substrates. The morphological and chemical effects of annealing at 525°C were investigated using X-ray Photoelectron Spectroscopy (XPS), X-ray-excited Auger electron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, and atomic force microscopy. We find a decrease of the Cd and Te surface concentration after annealing, parallel to an increase in Zn and O signals. While the as-deposited film surfaces show small grains (100nm diameter) of CdTe on the ZnO surface, annealing induces a significant growth of these grains and separation into islands (with diameters as large as 1μm). The compositional change at the surface is more pronounced for Cd than for Te, as evidenced using component peak fitting of the Cd and Te 3d XPS peaks. The modified Auger parameters of Cd and Te are also calculated to further elucidate the local chemical environment before and after annealing. Together, these results suggest the formation of tellurium and cadmium oxide species at the CdTe/ZnO interface upon annealing, which can create a barrier for charge carrier transport, and might allow for a deliberate modification of interface properties with suitably chosen thermal treatment parameters.",
author = "K. Horsley and Beal, {R. J.} and Wilks, {R. G.} and M. Blum and M. H{\"a}ming and Hanks, {D. A.} and Weir, {M. G.} and T. Hofmann and L. Weinhardt and M. B{\"a}r and Potter, {Barrett G} and C. Heske",
year = "2014",
month = "7",
day = "14",
doi = "10.1063/1.4890235",
language = "English (US)",
volume = "116",
journal = "Journal of Applied Physics",
issn = "0021-8979",
publisher = "American Institute of Physics Publising LLC",
number = "2",

}

TY - JOUR

T1 - Impact of annealing on the chemical structure and morphology of the thin-film CdTe/ZnO interface

AU - Horsley, K.

AU - Beal, R. J.

AU - Wilks, R. G.

AU - Blum, M.

AU - Häming, M.

AU - Hanks, D. A.

AU - Weir, M. G.

AU - Hofmann, T.

AU - Weinhardt, L.

AU - Bär, M.

AU - Potter, Barrett G

AU - Heske, C.

PY - 2014/7/14

Y1 - 2014/7/14

N2 - To enable an understanding and optimization of the optoelectronic behavior of CdTe-ZnO nanocomposites, the morphological and chemical properties of annealed CdTe/ZnO interface structures were studied. For that purpose, CdTe layers of varying thickness (4-24nm) were sputter-deposited on 100nm-thick ZnO films on surface-oxidized Si(100) substrates. The morphological and chemical effects of annealing at 525°C were investigated using X-ray Photoelectron Spectroscopy (XPS), X-ray-excited Auger electron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, and atomic force microscopy. We find a decrease of the Cd and Te surface concentration after annealing, parallel to an increase in Zn and O signals. While the as-deposited film surfaces show small grains (100nm diameter) of CdTe on the ZnO surface, annealing induces a significant growth of these grains and separation into islands (with diameters as large as 1μm). The compositional change at the surface is more pronounced for Cd than for Te, as evidenced using component peak fitting of the Cd and Te 3d XPS peaks. The modified Auger parameters of Cd and Te are also calculated to further elucidate the local chemical environment before and after annealing. Together, these results suggest the formation of tellurium and cadmium oxide species at the CdTe/ZnO interface upon annealing, which can create a barrier for charge carrier transport, and might allow for a deliberate modification of interface properties with suitably chosen thermal treatment parameters.

AB - To enable an understanding and optimization of the optoelectronic behavior of CdTe-ZnO nanocomposites, the morphological and chemical properties of annealed CdTe/ZnO interface structures were studied. For that purpose, CdTe layers of varying thickness (4-24nm) were sputter-deposited on 100nm-thick ZnO films on surface-oxidized Si(100) substrates. The morphological and chemical effects of annealing at 525°C were investigated using X-ray Photoelectron Spectroscopy (XPS), X-ray-excited Auger electron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, and atomic force microscopy. We find a decrease of the Cd and Te surface concentration after annealing, parallel to an increase in Zn and O signals. While the as-deposited film surfaces show small grains (100nm diameter) of CdTe on the ZnO surface, annealing induces a significant growth of these grains and separation into islands (with diameters as large as 1μm). The compositional change at the surface is more pronounced for Cd than for Te, as evidenced using component peak fitting of the Cd and Te 3d XPS peaks. The modified Auger parameters of Cd and Te are also calculated to further elucidate the local chemical environment before and after annealing. Together, these results suggest the formation of tellurium and cadmium oxide species at the CdTe/ZnO interface upon annealing, which can create a barrier for charge carrier transport, and might allow for a deliberate modification of interface properties with suitably chosen thermal treatment parameters.

UR - http://www.scopus.com/inward/record.url?scp=84904278453&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84904278453&partnerID=8YFLogxK

U2 - 10.1063/1.4890235

DO - 10.1063/1.4890235

M3 - Article

AN - SCOPUS:84904278453

VL - 116

JO - Journal of Applied Physics

JF - Journal of Applied Physics

SN - 0021-8979

IS - 2

M1 - 024312

ER -