Ultrasonic chemical bath deposition of ZnS(O,OH) buffer layers and its application to CIGS thin-film solar cells

Chemical bath deposition (CBD) is a fairly simple synthetic route to prepare II-VI semicondutive zinc sulfide thin films, which can be prepared on the flat surface of glass or silicon wafer substrates in the solution containing the precursors of zinc and sulfur ions in terms of ambient conditions of varying acidity. This study particularly aims at the growth dependence and optical property of ZnS thin films in the CBD process by different experiment parameters, whereas we intend to choose suitable types of zinc ionic precursors to be coupled with various CBD parameters such as reaction temperature and time, precursor concentration, types and complexing agents as well as post-deposition heat treatment conditions. Addition of different concentration of ethylenediamine, ammonium sulfate, sodium citrate and hydrazine in the CBD reaction process was used to control the adequate growth rate of ZnS thin films. As a consequence, the rapid thermal annealing was employed to enhance the film uniformity and thickness evenness, transmittance and the energy gap of ZnS samples. The results would lead to a potential application of buffer layer for the Cu (In,Ga)Se2 based thin film solar cells. The analytic instrument including SEM, AFM, UV-VIS were used to examine the CBD-derived nanosized ZnS buffer layers for the thin film solar cells. The ZnS thin films prepared by the chemical bath deposition in this study results in film thickness of 80 ~ 100 nm, high transmittance of 80~85% and the energy gap of 3.89 ~ 3.98 eV.

Download Full-text

Influence of chemical bath deposition parameters on the formation of CuInS2 / Zn(Se,O) junctions for thin film solar cells

MRS Proceedings ◽

10.1557/proc-668-h2.9 ◽

2001 ◽

Vol 668 ◽

Cited By ~ 8

Author(s):

A.M. Chaparro ◽

M.T. Gutiérrez ◽

J. Herrero ◽

J. Klaer

Keyword(s):

Thin Film ◽

Solar Cells ◽

Chemical Bath Deposition ◽

Open Circuit Potential ◽

Open Circuit ◽

Buffer Layers ◽

Thin Film Solar Cells ◽

Deposition Parameters ◽

Layer Deposition ◽

Cbd Method

ABSTRACTThin film solar cells of CuInS2/Zn(Se,O)/ZnO configuration have been studied as a function of the Zn(Se,O) buffer layer deposition parameters. Deposition of the buffer films was carried out by the chemical bath deposition (CBD) method, at different bath temperatures and compositions, and followed in situ with a quartz crystal microbalance. The CBD conditions were chosen to grow Zn(Se,O) buffer layers under different kinetic regimes but maintaining the same buffer thickness. The cells have been characterised with current-voltage and quantum efficiency measurements. Light soaking effects and medium term stability have been checked. It is found that Zn(Se,O) grown under predominant electroless kinetics gives rise to buffer films richer in oxygen, which allow for higher fill factors, higher efficiencies (around 10%) and stability of the cells. These cells show however lower open circuit potential. On the other hand, Zn(Se,O) buffers grown under chemical regime become richer in selenium, which gives rise to cells with higher open circuit potential, but lower fill factor, conversion efficiency and stability. Light soaking effects are also more important with the chemically grown buffers.

Download Full-text

Development of Cu(InGa)Se2 Thin Film Solar Cells with Cd-Free Buffer Layers

MRS Proceedings ◽

10.1557/proc-426-153 ◽

1996 ◽

Vol 426 ◽

Cited By ~ 33

Author(s):

M. Konagai ◽

Y. Ohtake ◽

T. Okamoto

Keyword(s):

Thin Film ◽

Solar Cells ◽

Buffer Layer ◽

Atomic Layer ◽

Buffer Layers ◽

Thin Film Solar Cells ◽

Light Illumination ◽

Solar Simulator ◽

Cell Parameters ◽

Cigs Thin Film

AbstractCu(InGa)Se2(CIGS) thin film absorbers were fabricated by a three-stage method using a coevaporation apparatus. As a Cd-free buffer layer, ZnSe, InxSe, GaxSey and ZnInxSey buffer layers have been deposited on the CIGS absorber continuously in the same apparatus. Atomic layer deposition (ALD) was employed as a growth technique for ZnSe. This technique offers a good thickness control as well as a good surface coverage. By irradiating with a solar simulator, all the solar cell parameters increased drastically for the first 50 minutes of the irradiation and then saturated at longer irradiation times. This phenomenon did not appear for the cells with a CdS buffer layer. The best efficiency of ZnO/ZnSe/CIGS thin film solar cells with about 10 nm thick ZnSe buffer layer was 11.6%. On the other hand, ZnO/InxSey/CIGS thin film solar cells showed very stable characteristics under the light illumination, and initial measurements show an efficiency of 13.0%.

Download Full-text