scholarly journals Thin Films with Low Zn Content Prepared by Chemical Bath Deposition

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Caijuan Tian ◽  
Jingjing Gao ◽  
Wei Li ◽  
Lianghuan Feng ◽  
Jingquan Zhang ◽  
...  

Chemical bath deposition (CBD) was used for the growth of thin films with low Zn content. The influence of preparation conditions, such as pH, temperature, and concentration, on film properties was investigated. The chemical growth mechanism of thin films was analyzed, and optimized growth conditions for the thin films were established. The fill factor and short-circuit current were improved while was used to replace CdS as the window layer in CdTe solar cells.

2003 ◽  
Vol 763 ◽  
Author(s):  
Akhlesh Gupta ◽  
Karthikeya Allada ◽  
Sung Hyun Lee ◽  
Alvin D. Compaan

AbstractIt is known that carriers photogenerated in the polycrystalline CdS layer of a CdS/CdTe cell are not collected. Thus, the short-circuit current (JSC) of CdS/CdTe devices should be improved if the bandgap of CdS is increased to permit better blue response. Wu, et al, showed that alloying of CdS with oxygen can increase the absorption edge of the layer. We report here on studies of this ‘oxygenated’ CdS and its use in sputtered cells. We find that at a deposition temperature of 250°C the addition of O2 to the sputter gas results in a red shift of the absorption edge (from 2.35 eV to 1.94 eV), but that room temperature deposition gives a blue shift (from 2.36 eV to 3.28 eV). The Raman spectra of the room temperature deposited films show a considerable broadening of LO phonon peaks suggesting a micro- to nano- to amorphous transition as the O2 fraction increases. XRD measurements of these films confirm the formation of an amorphous structure at high O2 fractions. The quantum efficiency measurements of CdS/CdTe device with room temperature deposited oxy-CdS show an improvement in blue response and hence increased JSC, but are accompanied by poorer junction quality so that the overall efficiency is not increased.


Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 291
Author(s):  
Xu He ◽  
Lili Wu ◽  
Xia Hao ◽  
Jingquan Zhang ◽  
Chunxiu Li ◽  
...  

Wider band-gap window layers can enhance the transmission of sunlight in the short-wavelength region and improve the performance of CdTe solar cells. In this work, we investigated the band structure of In-doped Zn1−xMgxO (ZMO:In) by using first-principles calculations with the GGA + U method and simulated the performance of ZMO:In/CdTe devices using the SCAPS program. The calculation results show that with the increased Mg doping concentration, the band gap of ZMO increases. However, the band gap of ZMO was decreased after In incorporation due to the downwards shifted conduction band. Owing to the improved short circuit current and fill factor, the conversion efficiency of the ZMO:In-based solar cells show better performance as compared with the CdS-based ones. A highest efficiency of 19.63% could be achieved owing to the wider band gap of ZMO:In and the appropriate conduction band offset (CBO) of ~0.23 eV at ZMO:In/CdTe interface when the Mg concentration x approaches 0.0625. Further investigations on thickness suggest an appropriate thickness of ZMO:In (x = 0.0625) in order to obtain better device performance would be 70–100 nm. This work provides a theoretical guidance for designing and fabricating highly efficient CdTe solar cells.


MRS Advances ◽  
2019 ◽  
Vol 4 (37) ◽  
pp. 2035-2042 ◽  
Author(s):  
L.A. Rodríguez-Guadarrama ◽  
I.L. Alonso-Lemus ◽  
J. Campos-Álvarez ◽  
J. Escorcia-García

ABSTRACTTernary Sn-Sb-S thin films with remarkable optical, electrical and structural properties were developed by chemical bath deposition. Tin and antimony chlorides and thioacetamide were used as tin, antimony, and sulfur ion sources, respectively, while tartaric acid was used as a complexing agent. XRD analysis of as-deposited films showed a combination of binary phases of SnS, Sn2S3, and Sb2S3, while after thermal treatment in nitrogen at 400 °C, the films became crystalline showing well-defined reflections of the ternary SnSb2S4. The heating also influenced the morphology, compactness, and thickness of the films. On the other hand, all the films showed an absorption coefficient higher than 104 cm-1, while the optical band gap of the as-deposited film decreased from 1.49 to 1.37 eV after heating at 400 °C. In addition, the photoconductivity of the films prior to heating was of 10-9 Ω-1 cm-1, while after that at 400 °C was of 10-7 Ω-1 cm-1. The evaluation of the ternary film in solar cells gave an open-circuit voltage Voc of 448 mV and short-circuit current density of Jsc of 2.4 mA/cm2.


Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 943
Author(s):  
Nowshad Amin ◽  
Mohammad Rezaul Karim ◽  
Zeid Abdullah ALOthman

In this paper, optical losses in CdS/CdTe solar cells are calculated on the basis of the designated reflective index of various frontal layers using an OPAL2 calculator for the first time. Two types of glass (0.1 mm ultra-thin Schott and 1.1 mm standard borosilicate glass) were assumed to be coated by different Transparent-Conducting-Oxides (TCOs) such as SnO2:F, ZnO:Al, and ITO forming frontal layers for CdS/CdTe solar cells in superstrate configuration. Absorption, reflectance, transmittance, and consequently optical bandgap energies are calculated as a function of common thicknesses, used in the literature. The results show that an increase in TCO thickness led to a decrease in optical band gap as well as an enhancement in contact potential difference, which can deteriorate device performance. The optimum thickness of 100 nm for SnO2:F was calculated, while 200 nm for ZnO:Al and ITO show reasonable optical losses caused by reflections at the interfaces’ and the layer’s absorption. It is seen that 80 to 150 nm CdS on ITO might be an effective range to satisfy a high short circuit current and low defect densities at the CdS/CdTe interface. Finally, a minimum 2 μm thickness for the CdTe on the ultra-thin Schott glass coated by optimum layers can result in the highest short circuit current of 28.69 mA/cm2. This work offers a practical equivalent strategy to be applied for any superstrate solar cells containing TCO and CdS frontal layers.


2019 ◽  
Vol 293 ◽  
pp. 111-123
Author(s):  
Paulina Boryło ◽  
Marek Szindler ◽  
Krzysztof Lukaszkowicz

This paper presents application examples of atomic layer deposition method (ALD) adopted for production of multifunctional thin films for various usage such as passive, antireflection and transparent conductive films. First part of this paper introduces the mechanism of ALD process, in the rest of it, aluminum oxide (as passive and antireflection) and zinc oxide (as antireflection and transparent conductive) ALD thin films are presented. In the literature one can find reports on the use of the Al2O3 layer as passivating and ZnO layers as a transparent conductive oxide in diodes, polymeric and dye sensitized solar cells. In this article, the ALD layers were tested for their use in silicon solar cells, using their good electrical and optical properties. For examination of prepared thin films characteristics, following research methods were used: scanning electron microscope, atomic force microscope, X-ray diffractometer, ellipsometer, UV/VIS spectrometer and resistance measurements. By depositing a layer thickness of about 80 nm, the short-circuit current on the surface of the solar cell was increased three times while reducing the reflection of light. In turn, by changing the deposition temperature of the ZnO thin film, you can control its electrical properties while maintaining high transparency. The obtained results showed that the ALD method provide the ability to produce a high quality multifunctional thin films with the required properties.


MRS Advances ◽  
2017 ◽  
Vol 2 (53) ◽  
pp. 3147-3156 ◽  
Author(s):  
Erenn Ore ◽  
Gehan Amaratunga ◽  
Stefaan De Wolf

ABSTRACTIn the conventional crystalline silicon heterojunction solar cell with the intrinsic thin layer structure (the HIT solar cell), a p-doped thin film silicon or its alloy (pDTF-Si/A) is used as the hole collecting window layer. However, the parasitic absorbance in the pDTF-Si/A window layer, and the toxic, explosive diborane gas used for p-doping are limiting factors for achieving HIT cells with reduced processing costs and / or higher efficiencies. In this work, pDTF-Si/A is replaced by V2Ox, which is deposited by a simple physical vapor deposition technique. Due to the wide band gap of V2Ox, the HIT solar cell with the V2Ox window layer generates a higher short-circuit current density than the reference conventional HIT cell under 1 sun, and achieves an open-circuit voltage of 0.7 V. Furthermore, the charge carrier lifetime and pseudo-efficiency values of the HIT solar cell with the V2Ox window layer indicate that this cell has the potential to outperform the conventional HIT cell in terms of the power conversation efficiency under the standard test conditions.


2019 ◽  
Vol 34 (04) ◽  
pp. 2050053
Author(s):  
Fatemeh Ghavami ◽  
Alireza Salehi

In this paper, the performance of copper-indium-gallium-diselenide Cu(In,Ga)Se2 solar cell, with ZnO window layer, ZnSe buffer layer, CIGS absorber layer and InGaP reflector layer was studied. The study was performed using the TCAD Silvaco simulator. The effects of grading the band gap of CIGS absorber layer, the various thicknesses and doping concentrations of different layers have been investigated. By optimizing the solar cell structure, we have obtained a maximum open circuit voltage of 0.91901 V, a short circuit current density of 39.89910 mA/cm2, a fill factor (FF) of 86.67040% and an efficiency of 31.78% which is much higher than the values for similar CIGS solar cells reported so far.


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