Vertically Arranged Zinc Oxide Nanorods as Antireflection Layer for Crystalline Silicon Solar Cell: A Simulation Study of Photovoltaic Properties (original) (raw)

ZnO Nanostructures as Efficient Antireflection Layers in Solar Cells

Nano Letters, 2008

An efficient antireflection coating (ARC) can enhance solar cell performance through increased light coupling. Here, we investigate solutiongrown ZnO nanostructures as ARCs for Si solar cells and compare them to conventional single layer ARCs. We find that nanoscale morphology, controlled through synthetic chemistry, has a great effect on the macroscopic ARC performance. Compared with a silicon nitride (SiN) single layer ARC, ZnO nanorod arrays display a broadband reflection suppression from 400 to 1200 nm. For a tapered nanorod array with average tip diameter of 10 nm, we achieve a weighted global reflectance of 6.6%, which is superior to an optimized SiN single layer ARC. Calculations using rigorous coupled wave analysis suggest that the tapered nanorod arrays behave like modified single layer ARCs, where the tapering leads to impedance matching between Si and air through a gradual reduction of the effective refractive index away from the surface, resulting in low reflection particularly at longer wavelengths and eliminating interference fringes through roughening of the air-ZnO interface. According to the calculations, we may further improve ARC performance by tailoring the thickness of the bottom fused ZnO layer and through better control of tip tapering.

A review of Effect the Zinc Oxide deposition on Crystalline Silicon Solar Cells

Proceedings of 2nd International Multi-Disciplinary Conference Theme: Integrated Sciences and Technologies, IMDC-IST 2021, 7-9 September 2021, Sakarya, Turkey, 2022

Zinc oxide (ZnO), a direct bandgap semiconductor, provides tremendous promise in various applications, such as optical waveguides, clear conductive oxides, and chemical gas sensors. It is also used in UV-light emitters, piezoelectric transducers. ZnO is in various forms, such as nanoparticles, Nano-belts, Nano-rods, nano-tubes, and nanowires. The purpose of this research is to review a general overview of ZnO and its application, the use of ZnO as an anti-reflection coating with various styles on the solar cells, and the conventional and unconventional techniques that had been used to coating the anti-reflection layers on the solar cell will be reviewed. This is based on a review of previous studies related to applications of anti-reflective coatings of ZnO and make a comparison of practical results was obtained with different semiconductor materials (SIC, TiO2, ZnS, SiO2, SiN4).

Deep traps in the ZnO nanorods/Si solar cells

Journal of Alloys and Compounds, 2017

Electric measurements were performed on solar cells composed of n-type ZnO nanorods grown by the hydrothermal method on p-type silicon substrate. The nanorods were covered with silver nanoparticles of sizes 20-30 nm and 50-60 nm. The diameters and density of the nanorods and nanoparticles were determined from scanning electron microscopy (SEM) and atomic force microscopy (AFM) images. On top of the structures the ZnO:Al (AZO) layer was deposited as a transparent electrode using the atomic layer deposition (ALD) method. The efficiency of the cells was found to be ~3.4%, however the sample with larger nanoparticles exhibit better performance. The analysis of the current-voltage (I-V) measurements vs illumination intensity let us conclude that the surface recombination deteriorates their performance. The measurements of capacitance-voltage (C-V) characteristics allowed us to determine the concentration of donors in ZnO and built-in voltage at the ZnO/Si interface. The deep level transient spectroscopy (DLTS) measurements confirmed the presence of defects at the surface as well as deeper in the ZnO nanorods. Obtained results compared with the data reported elsewhere let us conclude that the defect density is much less than in the case of similar heterojunction ZnO/Si solar cells made by other technological methods.

Effect of Zinc Oxide Antireflective Coatings on Crystalline Silicon Solar Cells

2015

Low temperature (200-325˚C) ECR (electron cyclotron resonance) plasma enhanced CVD has been used to deposit microcrystalline and epitaxial emitter layers in simple crystalline Si solar cell structures. Zinc Oxide (ZnO) transparent layers have been used on these silicon solar cells as anti-reflecting coatings (ARC). The RF magnetron sputtering technique was used for depositing these ZnO layers on silicon solar cells. The dependence of electrical and optical properties of the films as a function of substrate temperature and deposition pressure have been investigated. Films deposited at room temperature were highly resistive. A low resistivity value of 4.7x10-4 Ωcm could be achieved with increasing the deposition temperature up to ~ 350˚C. A thickness of 70-80 nm is optimum for use of the films as anti-reflection coatings. After ZnO ARC application, the cell efficiency could be improved up to 13.1% for an epitaxial emitter cell from the original value of 10.8%.

Photovoltaic properties of hybrid c-Si/ZnO nanorod solar cells

Materials Advances

A direct impact of the growth temperature, the nucleation and growth rates on the morphology, crystallinity, orientation and optical properties of the ZnO NRs arrays. A simulated optimum photo-conversion efficiency of 15.48% is achieved in ZnO NRs of 1.1 μm in length.

Photovoltaic properties of ZnO nanorods/p-type Si heterojunction structures

Beilstein journal of nanotechnology, 2014

Selected properties of photovoltaic (PV) structures based on n-type zinc oxide nanorods grown by a low temperature hydrothermal method on p-type silicon substrates (100) are investigated. PV structures were covered with thin films of Al doped ZnO grown by atomic layer deposition acting as transparent electrodes. The investigated PV structures differ in terms of the shapes and densities of their nanorods. The best response is observed for the structure containing closely-spaced nanorods, which show light conversion efficiency of 3.6%.

Improvement of the solar cell efficiency by the ZnO nanoparticle layer via the down-shifting effect

Microelectronic Engineering, 2014

External quantum efficiency a b s t r a c t A down-shifting material can generate one low-energy photon for every one incident high-energy photon. When such a material is placed on the front side of a photovoltaic solar cell, it has the potential to enhance the overall efficiency of the PV device by emitting photons in the spectral range where the solar cell efficiency is higher. This paper examines the application of ZnO nanoparticles as a luminescent down-shifting layer (LDSL) on the Si-based, CIGS and CdTe photovoltaic devices. The experimental results measured on a Si-based photovoltaic cell with a top luminescent down-shifting layer are analyzed.

ZnO Films with Tailored Material Properties for Highly Efficient Thin-Film Silicon Solar Modules

This study addresses the balance between electrical and optical properties of magnetron sputtered aluminum doped zinc oxide (ZnO:Al) films for the application as front contact in silicon thin-film solar cells and modules. We gradually decreased the amount of carrier concentration in the ZnO:Al films without any effect on surface topography. By reducing carrier concentration resistivity rose while parasitic free carrier absorption of the transparent conductive oxide in the near infrared decreased. The relationship between carrier concentration and short circuit current density of microcrystalline silicon (µc-Si:H) single junction thin-film solar cells has been studied experimentally. These data have been used to estimate optimal carrier concentration of the front TCO of single and multi junction modules. Besides, current enhancement by tailoring the charge carrier density, the opencircuit voltage was enhanced by in situ controlled SiH4 flow profiling during µc-Si:H deposition. In first promising results in triple junction a-Si:H / µc-Si:H / µc-Si:H modules (64 cm 2 ) we achieved an initial aperture area efficiency of 11.1%.