Growth of Cu2ZnSnS4 Thin Films Using Moderate Annealing Temperature and Short Dwell Time

Yıl 2019, Cilt: 40 Sayı: 3, 554 - 562, 30.09.2019

Mehmet Ali Olğar Ayşe Seyhan

https://doi.org/10.17776/csj.527260

Cited By: 1

Öz

In this study CZTS thin films were fabricated by
a two-stage process that sputter deposition of metallic Cu, Zn, and Sn on Mo
coated glass substrates and annealing process at 500 °C using various short
dwell times (4, 8, and 12 min) using Rapid Thermal Processing (RTP) approach.
The X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy
(SEM), Energy Dispersive X-ray Spectroscopy (EDX), and photoluminescence were
employed to characterize the CZTS samples synthesized employing different sulfurization
times. It was observed that all CZTS thin films showed Cu-poor and Zn-rich
composition according to EDX results. XRD patterns displayed formation of
kesterite CZTS and CuS secondary phases. Raman spectra of the films justified
formation of kesterite CZTS phase for all CZTS thin films and formation of CTS
phase, which is difficult to distinguish by XRD pattern of the films for CZTS-8
and CZTS-12 samples. SEM images of the films displayed dense, void-free, and
inhomogeneous surface structure regardless of the sulfurization time. The
optical band gap of the films as determined by photoluminescence was found to
be about 1.36-1.37 eV.

Anahtar Kelimeler

Cu2ZnSnS4, sputtering, annealing time, annealing temperature, RTP

Yüksek Olmayan Tavlama Sıcaklığı ve Kısa Bekleme Süresi Kullanılarak Cu2ZnSnS4 İnce Filmlerin Üretimi

Öz

Bu çalışmada CZTS ince
filmler iki-aşamalı yöntem kullanılarak üretildi; Mo kaplı cam üzerine saçtırma
yöntemiyle metalik Cu, Zn ve Sn katmanlarının kaplanması ve sonrasında bu
katmanlı yapının 500 °C sıcaklık ve farklı kısa sürelerde (4, 8 ve 12 dakika)
hızlı ısıl işlem (RTP) yaklaşımı ile tavlanması. Farklı tavlama süreleri ile
üretilen CZTS örnekler X-ışını kırınımı (XRD), Raman spektroskopisi, Taramalı
Elektron Mikroskobu (SEM), Enerji Dağılımlı X-ışını Spektroskopisi (EDX) ve
fotoluminesans teknikleri kullanılarak karakterize edilmiştir. Üretilen bütün
CZTS örneklerin Cu-fakiri ve Zn-zengini kimyasal kompozisyona sahip olduğu ve
XRD desenlerinde CZTS fazı oluşumun yanında CuS fazının da oluştuğu
görülmüştür. Raman spektroskopisi ile hem CZTS fazının oluştuğu doğrulanmış
olup hem de XRD ile ayırt edilemeyen CTS fazının oluştuğu tespit edilmiştir.
SEM ile elde edilen film yüzey görüntülerinin sülfürleme süresinden bağımsız
olarak yoğun, deliksiz ve homojen olmayan bir yapıya sahip oldukları tespit
edilmiştir. Fotolüminesans spektrumları ile optik yasak enerji aralığının
1.36-137 civarında olduğu belirlenmiştir.

Anahtar Kelimeler

Cu2ZnSnS4, saçtırma, tavlama süresi; tavlama sıcaklığı

Kaynakça

• [1] Kato T., Wu J.L., Hirai Y., Sugimoto H., Bermudez V., Record Efficiency for Thin-Film Polycrystalline Solar Cells Up to 22.9% Achieved by Cs-Treated Cu(In,Ga)(Se,S)(2), Ieee J. Photovolt., 9 (2019) 325-330.
• [2] Katagiri H., Sasaguchi N., Hando S., Hoshino S., Ohashi J. and Yokota T., Preparation and evaluation of Cu2ZnSnS4 thin films by sulfurization of E-B evaporated precursors, Sol. Energ. Mat. Sol. C., 49 (1997) 407-414.
• [3] Shockley W. and Queisser H.J., Detailed Balance Limit of Efficiency of p‐n Junction Solar Cells, JPN J. Appl. Phys., 32 (1961) 510-519.
• [4] Wang W., Winkler M.T., Gunawan O., Gokmen T., Todorov T.K., Zhu Y. and Mitzi D.B., Device Characteristics of CZTSSe Thin-Film Solar Cells with 12.6% Efficiency, Adv. Energy Mater., 4 (2014) 1301465.
• [5] Wang K., Gunawan O., Todorov T., Shin B., Chey S.J., Bojarczuk N.A., Mitzi D. and Guha S., Thermally evaporated Cu2ZnSnS4 solar cells, Appl. Phys. Lett., 97 (2010) 143508.
• [6] Mkawi E.M., Al-Hadeethi Y., Shalaan E. and Bekyarova E., Substrate temperature effect during the deposition of (Cu/Sn/Cu/Zn) stacked precursor CZTS thin film deposited by electron-beam evaporation, J. Mater. Sci-Mater. El., 29 (2018) 20476-20484.
• [7] Olgar M.A., Optimization of sulfurization time and temperature for fabrication of Cu2ZnSnS4 (CZTS) thin films, Superlattice Microst., 126 (2019) 32-41.
• [8] Vanalakar S.A., Agawane G.L., Shin S.W., Suryawanshi M.P., Gurav K.V., Jeon K.S., Patil P.S., Jeong C.W., Kim J.Y. and Kim J.H., A review on pulsed laser deposited CZTS thin films for solar cell applications, J. Alloy. Compd., 619 (2015) 109-121.
• [9] Tanaka K., Fukui Y., Moritake N. and Uchiki H., Chemical composition dependence of morphological and optical properties of Cu2ZnSnS4 thin films deposited by sol-gel sulfurization and Cu2ZnSnS4 thin film solar cell efficiency, Sol. Energ. Mat. Sol. C., 95 (2011) 838-842.
• [10] Hamada T., Fukuyama A., Jiang F., Ikeda S. and Ikari T., Effect of preheating time on uniformity of electrodeposited Cu2ZnSnS4 thin films studied by carrier lifetime and photoluminescence measurements, Phys. Status Solidi C., 12 (2015) 725-728.
• [11] Hages C.J., Levcenco S., Miskin C.K., Alsmeier J.H., Abou-Ras D., Wilks R.G., Bar M., Unold T. and Agrawal R., Improved performance of Ge-alloyed CZTGeSSe thin-film solar cells through control of elemental losses, Prog. Photovoltaics, 23 (2015) 376-384.
• [12] Tanaka K., Kato M., Goto K., Nakano Y. and Uchiki H., Face-to-Face Annealing Process of Cu2ZnSnS4 Thin Films Deposited by Spray Pyrolysis Method, Jpn. J. Appl. Phys., 51 (2012) 10S.
• [13] Emrani A., Vasekar P. and Westgate C.R., Effects of sulfurization temperature on CZTS thin film solar cell performances, Sol. Energy, 98 (2013) 335-340.
• [14] Guan H., Shen H.L., Gao C. and He X.C., Sulfurization time effects on the growth of Cu2ZnSnS4 thin films by solution method, J. Mater. Sci-Mater. El., 24 (2013) 2667-2671.
• [15] Olgar M.A., Klaer J., Mainz R., Levcenco S., Just J., Bacaksiz E. and Unold T., Effect of precursor stacking order and sulfurization temperature on compositional homogeneity of CZTS thin films, Thin Solid Films, 615 (2016) 402-408.
• [16] Olgar M.A., Atasoy Y., Basol B.M., Tomakin M., Aygun G., Ozyuzer L. and Bacaksiz E., Influence of copper composition and reaction temperature on the properties of CZTSe thin films, J. Alloy. Compd., 682 (2016) 610-617.
• [17] Espindola-Rodriguez M., Placidi M., Vigil-Galan O., Izquierdo-Roca V., Fontane X., Fairbrother A., Sylla D., Saucedo E. and Perez-Rodriguez A., Compositional optimization of photovoltaic grade Cu2ZnSnS4 films grown by pneumatic spray pyrolysis, Thin Solid Films, 535 (2013) 67-72.
• [18] Olgar M.A., Bacaksiz E., Tomakin M., Kucukomeroglu T. and Basol B.M., CZTS layers formed under sulfur-limited conditions at above atmospheric pressure, Mat. Sci. Semicon. Proc., 90 (2019) 101-106.
• [19] He J., Sun L., Chen Y., Jiang J.C., Yang P.X. and Chu J.H., Influence of sulfurization pressure on Cu2ZnSnS4 thin films and solar cells prepared by sulfurization of metallic precursors, J. Power Sources, 273 (2015) 600-607.
• [20] Weber A., Mainz R. and Schock H., On the Sn loss from thin films of the material system Cu–Zn–Sn–S in high vacuum, J. Appl. Phys., 107 (2010) 013516.
• [21] Olgar M.A., Basol B.M., Tomakin M., Seyhan A., Bacaksiz E., Influence of pre-annealing Cu-Sn on the structural properties of CZTSe thin films grown by a two-stage process, Mat. Sci. Semicon. Proc., 88 (2018) 234-238.
• [22] Gurav S.V., Pawar S.M., Shin S.W., Suryawanshi M.P., Agawane G.L., Patil P.S., Moon J.H., Yun J.H. and Kim J.H., Electrosynthesis of CZTS films by sulfurization of CZT precursor: Effect of soft annealing treatment, Appl. Surf. Sci., 283 (2013) 74-80. [23] Lin Y.-P., Hsieh T.-E., Chen Y.-C. and Huang K.-P., Characteristics of Cu2ZnSn(SxSe1− x)4 thin-film solar cells prepared by sputtering deposition using single quaternary Cu2ZnSnS4 target followed by selenization/sulfurization treatment, Sol. Energ. Mat. Sol. C., 162 (2017) 55-61.
• [24] Olgar M.A., Klaer J., Mainz R., Ozyuzer L. and Unold T., Cu2ZnSnS4-based thin films and solar cells by rapid thermal annealing processing, Thin Solid Films, 628 (2017) 1-6.
• [25] Fernandes P., Salomé P. and Da Cunha A., CuxSnSx+1 (x= 2, 3) thin films grown by sulfurization of metallic precursors deposited by dc magnetron sputtering, Physica Status Solidi C, 7 (2010) 901-904.
• [26] Chaudhuri T.K. and Tiwari D., Earth-abundant non-toxic Cu2ZnSnS4 thin films by direct liquid coating from metal–thiourea precursor solution, Sol. Energ. Mat. Sol. C, 101 (2012) 46-50.