Thin Gallium Arsenide Solar Cells With Maskless Back Surface Reflectors

D'Rozario, Julia R.; Polly, Stephen J.; Nelson, George T.; Hubbard, Seth M.

doi:10.1109/jphotov.2020.3019950

Cited by 16 publications

(4 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mode coupling requires an overlap between the characteristic spatial frequencies in the scattering profile of a textured surface and those of the waveguide modes supported by the device stack. Randomly rough surfaces can enable light-trapping mechanisms, − but their scattering profiles approach a Lambertian distribution and lead to weak resonances together with significant escape cone losses. Ordered photonic crystals have highly localized diffraction profiles and offer strong coupling to optical modes at specific wavelengths, − with corresponding absorption enhancements that can exceed the Lambertian limit .…”

Section: Introductionmentioning

confidence: 99%

Transparent Quasi-Random Structures for Multimodal Light Trapping in Ultrathin Solar Cells with Broad Engineering Tolerance

2022

View full text Add to dashboard Cite

Waveguide modes are well-known to be a valuable light-trapping resource for absorption enhancement in solar cells. However, their scarcity in the thinnest device stacks compromises the multiresonant performance required to reach the highest efficiencies in ultrathin devices. We demonstrate that enriching the modal structure on such reduced length-scales is possible by integrating transparent semiconductor/dielectric scattering structures to the device architecture as opposed to more widely studied metallic textures. This phenomenon allows transparent quasi-random structures to emerge as strong light-trapping candidates for ultrathin solar cells, given that their broad scattering profiles are well-suited to exploit the increased number of waveguide modes for multiresonant absorption enhancement. A thorough study of the design space of quasi-random textures comprising more than 1500 designs confirms the superiority of transparent structures over a metallic embodiment, identifies broad and flexible design requirements to achieve optimal performances, and demonstrates photon harvesting capabilities leading to 20% efficiency with an 80 nm GaAs absorber. Our light-trapping strategy can be applied to a wide range of material systems and device architectures, is compatible with scalable low-cost fabrication techniques, and can assist current trends to reach the highest efficiencies in ever-thinner photovoltaics.

show abstract

Section: Introductionmentioning

confidence: 99%

Transparent Quasi-Random Structures for Multimodal Light Trapping in Ultrathin Solar Cells with Broad Engineering Tolerance

2022

View full text Add to dashboard Cite

show abstract

“…For ultrathin GaAs there are two main approaches: using simple periodic structures [12], or roughening by using anisotropic wet etching [13,24]. The simple periodic approach has the advantage of obtaining the optimal scatterers if the design is accurate, while using a pre-produced stamp with a higher cost.…”

Section: Introductionmentioning

confidence: 99%

Efficient light-trapping in ultrathin GaAs solar cells using quasi-random photonic crystals

Buencuerpo,

Saenz,

Steger

et al. 2022

Preprint

View full text Add to dashboard Cite

Ultrathin solar cells reduce material usage and allow the use of lower-quality materials thanks to their one order of magnitude smaller thickness than their conventional counterparts. However, efficient photonic light-trapping is required to harvest the incident light efficiently for an otherwise insufficient absorber thickness. Quasi-random photonic crystals are predicted to have high efficient light-trapping while being more robust under angle and thickness variations than simple photonic crystals. Here we experimentally demonstrate a light-trapping solution based on quasi-random photonic crystals fabricated by polymer blend lithography. We control the average lattice parameter by modifying the spin-coating speed. We demonstrate an ultrathin GaAs cell of 260 nm with a rear quasi-random pattern with submicron features, and a J sc =26.4 mA/cm 2 and an efficiency of 22.35% under the global solar spectrum.

show abstract

“…7 With a suitable light-trapping scheme increasing the path length through the solar cell, the ultrathin structures can be made optically thick and achieve current-densities matching those of conventional thin film (2-3 μm) GaAs cells. [8][9][10] Light-managing structures in GaAs solar cells include front side nano-structures like plasmonic scattering particles, 11 textured window layers, 12,13 and dielectrics, 14,15 as well as rear side scattering layers with metallic mirrors, like transferred textured substrates, 16 dielectric nanostructures, 17 gratings, 18 (anisotropically) etched III-V layers, [19][20][21][22] and as-grown surfaces. 23,24 However, none of these methods meet all the important criteria for light-trapping structures that can be applied in large-scale production, namely, simplicity, reproducibility, cost-effectiveness, and close-to-zero parasitic absorption of high-energy photons above the GaAs bandgap.…”

Section: Introductionmentioning

confidence: 99%

Ultrathin GaAs solar cells with a high surface roughness GaP layer for light‐trapping application

Woude

Krabben

Bauhuis

et al. 2022

Progress in Photovoltaics

View full text Add to dashboard Cite

By reducing the thickness of the absorber layers, ultrathin GaAs solar cells can be fabricated in a more cost-effective manner using less source material and shorter deposition times. In this work, ultrathin GaAs solar cells are presented with a diffuse scattering layer based on wide bandgap GaP grown directly on the device layers of the cells with MOCVD. The roughness and surface morphology are quantified using atomic force microscopy and the resulting diffuse scattering capability is assessed using wavelength-dependent reflectance measurements. Ohmic rear contacts are made using contact points etched through the GaP layer, for which an etching procedure using I 2 :KI was developed and optimized. The performance of the GaP textured ultrathin GaAs cells are compared with equivalent planar cells using current densityvoltage measurements and external quantum efficiency measurements, where the GaP textured cells demonstrate an increase of 6.7% in the short-circuit current density (J SC ), which was found to be as high as 21.9 mAÁcm À2 as a result of increased photon absorption by light-trapping.

show abstract

Thin Gallium Arsenide Solar Cells With Maskless Back Surface Reflectors

Cited by 16 publications

References 29 publications

Transparent Quasi-Random Structures for Multimodal Light Trapping in Ultrathin Solar Cells with Broad Engineering Tolerance

Transparent Quasi-Random Structures for Multimodal Light Trapping in Ultrathin Solar Cells with Broad Engineering Tolerance

Efficient light-trapping in ultrathin GaAs solar cells using quasi-random photonic crystals

Ultrathin GaAs solar cells with a high surface roughness GaP layer for light‐trapping application

Contact Info

Product

Resources

About