Performance improvement for epitaxially grown SiGe on Si solar cell using a compositionally graded SiGe base

Li, Dun; Zhao, Xin; Wang, Li; Conrad, Brianna; Soeriyadi, Anastasia; Lochtefeld, A.; Gerger, Andrew; Perez-Würfl, Ivan; Barnett, Allen

doi:10.1063/1.4972034

Cited by 7 publications

(4 citation statements)

References 21 publications

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“…Some characteristics competitive with silicon are the higher carrier mobility and the smaller bandgap, being still fully compatible with complementary metal-oxide-semiconductor (CMOS) technology [2]. Other interesting applications for Ge are in the field of optoelectronics devices like photodetectors [3][4][5][6][7][8][9], photodiodes [4,10], photovoltaics [11][12][13][14][15], since the smaller bandgap compared to Si can allow the absorption of photons with larger wavelengths up to the near-infrared and beyond. In photonic devices the conversion efficiency is strongly limited by high reflectivity at the semiconductor surfaces, strongly affecting photon absorption in the active layer.…”

Section: Introductionmentioning

confidence: 99%

Omnidirectional and broadband photon harvesting in self-organized Ge columnar nanovoids

Chowdhury¹,

Mondal²,

Secchi³

et al. 2022

Nanotechnology

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Highly porous Germanium surfaces with uniformly distributed columnar nanovoid structures are fabricated over a large area (wafer scale) by large fluence Sn+ irradiation through a thin silicon nitride layer. The latter represents a one-step highly reproducible approach with no material loss to strongly increase photon harvesting into a semiconductor active layer by exploiting the moth-eye anti-reflection effect. The ion implantation through the nitride cap layer allows fabricating porous nanostructures with a high aspect ratio, which can be tailored by varying ion fluence. By comparing the reflectivity of nanoporous Ge films with a flat reference we demonstrate a strong and omnidirectional reduction in the optical reflectivity by a factor 96% in selected spectral regions around 960nm and by a factor 67.1% averaged over the broad spectral range from 350nm to 1800 nm. Such highly anti-reflective nanostructured Ge films prepared over large areas with a self-organized maskless approach have the potential to impact real-world applications aiming at energy harvesting.

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Section: Introductionmentioning

confidence: 99%

Omnidirectional and broadband photon harvesting in self-organized Ge columnar nanovoids

Chowdhury¹,

Mondal²,

Secchi³

et al. 2022

Nanotechnology

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“…SiO 2 is the most suitable matrix because of its compatibility with the CMOS technology and because it forms the best interface with Si substrate. These efforts are made with the purpose of improving the optoelectronic devices on Si and enabling the SiGe NCs integration in a large area of applications such as non-volatile memories [18][19][20] , GeSi based high-mobility transistors 21 , photo-MOSFETs 22 , solar cells [23][24][25] , thermoelectric applications 26 and high-performance photodetectors 7,[27][28][29][30] .…”

mentioning

confidence: 99%

SiGe nanocrystals in SiO2 with high photosensitivity from visible to short-wave infrared

Stavarache

Logofatu

Sultan

et al. 2020

Sci Rep

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Films of SiGe nanocrystals (NCs) in oxide have the advantage of tuning the energy band gap by adjusting SiGe NCs composition and size. In this study, SiGe-SiO2 amorphous films were deposited by magnetron sputtering on Si substrate followed by rapid thermal annealing at 700, 800 and 1000 °C. We investigated films with Si:Ge:SiO2 compositions of 25:25:50 vol.% and 5:45:50 vol.%. TEM investigations reveal the major changes in films morphology (SiGe NCs with different sizes and densities) produced by Si:Ge ratio and annealing temperature. XPS also show that the film depth profile of SiGe content is dependent on the annealing temperature. These changes strongly influence electrical and photoconduction properties. Depending on annealing temperature and Si:Ge ratio, photocurrents can be 103 times higher than dark currents. The photocurrent cutoff wavelength obtained on samples with 25:25 vol% SiGe ratio decreases with annealing temperature increase from 1260 nm in SWIR for 700 °C annealed films to 1210 nm for those at 1000 °C. By increasing Ge content in SiGe (5:45 vol%) the cutoff wavelength significantly shifts to 1345 nm (800 °C annealing). By performing measurements at 100 K, the cutoff wavelength extends in SWIR to 1630 nm having high photoresponsivity of 9.35 AW−1.

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“…A compromise is to use active SiGe as the bottom cell and GaAsP as its top cell to implement a bandgap combination close to GaAsP/Si. This GaAsP/SiGe dual-junction device was demonstrated in [23][24][25][26][27][28].…”

Section: Graded Simentioning

confidence: 99%

A review of recent progress in heterogeneous silicon tandem solar cells

Yamaguchi

Lee

Araki

et al. 2018

J. Phys. D: Appl. Phys.

123

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Silicon solar cells are the most established solar cell technology and are expected to dominate the market in the near future. As state-of-the-art silicon solar cells are approaching the Shockley–Queisser limit, stacking silicon solar cells with other photovoltaic materials to form multi-junction devices is an obvious pathway to further raise the efficiency. However, many challenges stand in the way of fully realizing the potential of silicon tandem solar cells because heterogeneously integrating silicon with other materials often degrades their qualities. Recently, above or near 30% silicon tandem solar cell has been demonstrated, showing the promise of achieving high-efficiency and low-cost solar cells via silicon tandem. This paper reviews the recent progress of integrating solar cell with other mainstream solar cell materials. The first part of this review focuses on the integration of silicon with III–V semiconductor solar cells, which is a long-researched topic since the emergence of III–V semiconductors. We will describe the main approaches—heteroepitaxy, wafer bonding and mechanical stacking—as well as other novel approaches. The second part introduces the integration of silicon with polycrystalline thin-film solar cells, mainly perovskites on silicon solar cells because of its rapid progress recently. We will also use an analytical model to compare the material qualities of different types of silicon tandem solar cells and project their practical efficiency limits.

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Performance improvement for epitaxially grown SiGe on Si solar cell using a compositionally graded SiGe base

Cited by 7 publications

References 21 publications

Omnidirectional and broadband photon harvesting in self-organized Ge columnar nanovoids

Omnidirectional and broadband photon harvesting in self-organized Ge columnar nanovoids

SiGe nanocrystals in SiO2 with high photosensitivity from visible to short-wave infrared

A review of recent progress in heterogeneous silicon tandem solar cells

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