Abstract

Silicon solar cells are presently dominant for harvesting solar energy because of the well-known production technology, but silicon has a low absorption such that a cell requires a layer of up to 200 µm silicon for sufficient light absorption. During the latest decades new thin-film semiconductor cells with a four-component absorber, e.g. CZTS (Cu2ZnSnS4), have emerged as promising candidates for solar energy. This material consists of abundant and non-toxic elements. The material has a direct absorption and the absorber works perfectly with a thickness of 1-2 µm. Films of this four-component material are difficult to make by pulsed laser deposition (PLD), because of the different physical properties of the elements in the target both for one-phase targets of CZTS and for composite targets of sulfides. One further complication is that the stoichiometry of the most efficient absorbers are different from the nominal composition mentioned above, i.e. the film has to be Cu-poor and Zn rich. After the production at room temperature the (amorphous) film has to be annealed in a furnace at a temperature up to 600 C with a sulfur atmosphere in order to form CZTS. In addition, Sn has to be added during the annealing as well. At low fluence it was possible to obtain a Cu-poor composition for CZTS such that a cell of more than 5 % efficiency could be produced [1]. Also the usual problem for PLD, large droplets, could be reduced at low fluence.
In order to avoid evaporation of the volatile SnS from the composite target during deposition we have replaced the sulfide target with a target of copper zinc tin oxide (CZTO). The SnO binary compound in CZTOis much less volatile than SnS, such that the final content of Sn in the deposited film can be controlled much better. During the annealing in the sulfur atmosphere the oxide in the film is completely converted to sulfide. A general trend is that the Cu/Sn ratio of the film decreases strongly with decreasing fluence for the oxide film similar to the behavior of the sulfide film previously reported [2]. The underlying physics of the behavior of the film composition as a function of laser fluence for a number of chalcogenides will be discussed in terms of the physical properties of the materials, in particular the cohesive energy. With the oxide target we has obtained the world record, 5.4 % , in efficiency for solar cell absorbers of CZTS produced by PLD
Original languageEnglish
Publication date2019
Publication statusPublished - 2019
Event15th International Conference on Laser Ablation - The Westin Maui Resort & Spa, Kaanapali, Maui, United States
Duration: 8 Sep 201913 Sep 2019
https://cola2019.org/

Conference

Conference15th International Conference on Laser Ablation
LocationThe Westin Maui Resort & Spa, Kaanapali
CountryUnited States
CityMaui
Period08/09/201913/09/2019
Internet address

Cite this

@conference{98e2898778674fa3b6cf36641e299fff,
title = "Thin films of CZTS and CZTO for solar cells produced by pulsed laser deposition",
abstract = "Silicon solar cells are presently dominant for harvesting solar energy because of the well-known production technology, but silicon has a low absorption such that a cell requires a layer of up to 200 µm silicon for sufficient light absorption. During the latest decades new thin-film semiconductor cells with a four-component absorber, e.g. CZTS (Cu2ZnSnS4), have emerged as promising candidates for solar energy. This material consists of abundant and non-toxic elements. The material has a direct absorption and the absorber works perfectly with a thickness of 1-2 µm. Films of this four-component material are difficult to make by pulsed laser deposition (PLD), because of the different physical properties of the elements in the target both for one-phase targets of CZTS and for composite targets of sulfides. One further complication is that the stoichiometry of the most efficient absorbers are different from the nominal composition mentioned above, i.e. the film has to be Cu-poor and Zn rich. After the production at room temperature the (amorphous) film has to be annealed in a furnace at a temperature up to 600 C with a sulfur atmosphere in order to form CZTS. In addition, Sn has to be added during the annealing as well. At low fluence it was possible to obtain a Cu-poor composition for CZTS such that a cell of more than 5 {\%} efficiency could be produced [1]. Also the usual problem for PLD, large droplets, could be reduced at low fluence. In order to avoid evaporation of the volatile SnS from the composite target during deposition we have replaced the sulfide target with a target of copper zinc tin oxide (CZTO). The SnO binary compound in CZTOis much less volatile than SnS, such that the final content of Sn in the deposited film can be controlled much better. During the annealing in the sulfur atmosphere the oxide in the film is completely converted to sulfide. A general trend is that the Cu/Sn ratio of the film decreases strongly with decreasing fluence for the oxide film similar to the behavior of the sulfide film previously reported [2]. The underlying physics of the behavior of the film composition as a function of laser fluence for a number of chalcogenides will be discussed in terms of the physical properties of the materials, in particular the cohesive energy. With the oxide target we has obtained the world record, 5.4 {\%} , in efficiency for solar cell absorbers of CZTS produced by PLD",
author = "Mungunshagai Gansukh and Martinho, {Filipe Mesquita Alves} and Mari{\~n}o, {Sim{\'o}n L{\'o}pez} and Eugen Stamate and {Espindola Rodriguez}, Moises and Engberg, {Sara Lena Josefin} and Ole Hansen and Stela Canulescu and J{\o}rgen Schou",
year = "2019",
language = "English",
note = "15th International Conference on Laser Ablation, COLA 2019 ; Conference date: 08-09-2019 Through 13-09-2019",
url = "https://cola2019.org/",

}

Thin films of CZTS and CZTO for solar cells produced by pulsed laser deposition. / Gansukh, Mungunshagai; Martinho, Filipe Mesquita Alves; Mariño, Simón López; Stamate, Eugen; Espindola Rodriguez, Moises; Engberg, Sara Lena Josefin; Hansen, Ole; Canulescu, Stela; Schou, Jørgen.

2019. Abstract from 15th International Conference on Laser Ablation, Maui, United States.

Research output: Contribution to conferenceConference abstract for conferenceResearchpeer-review

TY - ABST

T1 - Thin films of CZTS and CZTO for solar cells produced by pulsed laser deposition

AU - Gansukh, Mungunshagai

AU - Martinho, Filipe Mesquita Alves

AU - Mariño, Simón López

AU - Stamate, Eugen

AU - Espindola Rodriguez, Moises

AU - Engberg, Sara Lena Josefin

AU - Hansen, Ole

AU - Canulescu, Stela

AU - Schou, Jørgen

PY - 2019

Y1 - 2019

N2 - Silicon solar cells are presently dominant for harvesting solar energy because of the well-known production technology, but silicon has a low absorption such that a cell requires a layer of up to 200 µm silicon for sufficient light absorption. During the latest decades new thin-film semiconductor cells with a four-component absorber, e.g. CZTS (Cu2ZnSnS4), have emerged as promising candidates for solar energy. This material consists of abundant and non-toxic elements. The material has a direct absorption and the absorber works perfectly with a thickness of 1-2 µm. Films of this four-component material are difficult to make by pulsed laser deposition (PLD), because of the different physical properties of the elements in the target both for one-phase targets of CZTS and for composite targets of sulfides. One further complication is that the stoichiometry of the most efficient absorbers are different from the nominal composition mentioned above, i.e. the film has to be Cu-poor and Zn rich. After the production at room temperature the (amorphous) film has to be annealed in a furnace at a temperature up to 600 C with a sulfur atmosphere in order to form CZTS. In addition, Sn has to be added during the annealing as well. At low fluence it was possible to obtain a Cu-poor composition for CZTS such that a cell of more than 5 % efficiency could be produced [1]. Also the usual problem for PLD, large droplets, could be reduced at low fluence. In order to avoid evaporation of the volatile SnS from the composite target during deposition we have replaced the sulfide target with a target of copper zinc tin oxide (CZTO). The SnO binary compound in CZTOis much less volatile than SnS, such that the final content of Sn in the deposited film can be controlled much better. During the annealing in the sulfur atmosphere the oxide in the film is completely converted to sulfide. A general trend is that the Cu/Sn ratio of the film decreases strongly with decreasing fluence for the oxide film similar to the behavior of the sulfide film previously reported [2]. The underlying physics of the behavior of the film composition as a function of laser fluence for a number of chalcogenides will be discussed in terms of the physical properties of the materials, in particular the cohesive energy. With the oxide target we has obtained the world record, 5.4 % , in efficiency for solar cell absorbers of CZTS produced by PLD

AB - Silicon solar cells are presently dominant for harvesting solar energy because of the well-known production technology, but silicon has a low absorption such that a cell requires a layer of up to 200 µm silicon for sufficient light absorption. During the latest decades new thin-film semiconductor cells with a four-component absorber, e.g. CZTS (Cu2ZnSnS4), have emerged as promising candidates for solar energy. This material consists of abundant and non-toxic elements. The material has a direct absorption and the absorber works perfectly with a thickness of 1-2 µm. Films of this four-component material are difficult to make by pulsed laser deposition (PLD), because of the different physical properties of the elements in the target both for one-phase targets of CZTS and for composite targets of sulfides. One further complication is that the stoichiometry of the most efficient absorbers are different from the nominal composition mentioned above, i.e. the film has to be Cu-poor and Zn rich. After the production at room temperature the (amorphous) film has to be annealed in a furnace at a temperature up to 600 C with a sulfur atmosphere in order to form CZTS. In addition, Sn has to be added during the annealing as well. At low fluence it was possible to obtain a Cu-poor composition for CZTS such that a cell of more than 5 % efficiency could be produced [1]. Also the usual problem for PLD, large droplets, could be reduced at low fluence. In order to avoid evaporation of the volatile SnS from the composite target during deposition we have replaced the sulfide target with a target of copper zinc tin oxide (CZTO). The SnO binary compound in CZTOis much less volatile than SnS, such that the final content of Sn in the deposited film can be controlled much better. During the annealing in the sulfur atmosphere the oxide in the film is completely converted to sulfide. A general trend is that the Cu/Sn ratio of the film decreases strongly with decreasing fluence for the oxide film similar to the behavior of the sulfide film previously reported [2]. The underlying physics of the behavior of the film composition as a function of laser fluence for a number of chalcogenides will be discussed in terms of the physical properties of the materials, in particular the cohesive energy. With the oxide target we has obtained the world record, 5.4 % , in efficiency for solar cell absorbers of CZTS produced by PLD

M3 - Conference abstract for conference

ER -

Gansukh M, Martinho FMA, Mariño SL, Stamate E, Espindola Rodriguez M, Engberg SLJ et al. Thin films of CZTS and CZTO for solar cells produced by pulsed laser deposition. 2019. Abstract from 15th International Conference on Laser Ablation, Maui, United States.