Optimization of an i-a-SiOx:H absorber layer for thin film silicon solar cell applications

Sritharathikhun, Jaran; Inthisang, Sorapong; Krajangsang, Taweewat; Limmanee, Amornrat; Sriprapha, Kobsak

doi:10.1016/j.tsf.2013.05.138

Cited by 11 publications

(8 citation statements)

References 14 publications

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“…and ). Despite the decreasing electronical quality of the (i)a‐SiO:H absorber layer the photoresponse PR at r c = 1.2 of our layers was remarkably higher than 8 × 10 5 and was also higher than any reported value of others groups to our knowledge .…”

Section: Discussioncontrasting

confidence: 77%

“…It has already been shown by different groups that (i)a‐SiO:H is a promising material that provides a wide bandgap and good photoresponse, however, triple‐junction cells including an a‐SiO:H top cell reached only efficiencies close to 12% in laboratory scale . These results suffered from a low J sc due to not properly optimised current matching.…”

Section: Introductionmentioning

confidence: 99%

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Characterisation of intrinsic silicon oxide absorber layers for use in silicon thin film solar cells

Holinski

Borchert

Hohage

et al. 2015

Phys. Status Solidi A

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The use of a wide bandgap absorber layer in the top cell of a multi-junction silicon thin film solar cell is necessary to achieve a high-conversion efficiency. A higher bandgap of the absorber results in a higher open-circuit voltage (Voc) of the cell. In this work, intrinsic hydrogenated amorphous silicon oxide (i)a-SiO:H films have been prepared by using 13.56 MHz radio frequency plasma enhanced chemical vapour deposition (RF-PECVD) at a substrate temperature of 195 °C. The carbon dioxide (CO2) to silane (SiH4) ratio rc was varied and the influence of the ratio rc on the optoelectronic film properties was investigated. These thin films have been studied in detail in terms of their dark (σd) and photo (σph) conductivity and photoresponse PR (σph/σd). The defect density Nd and Urbach energy EU were determined by constant photocurrent method (CPM). The optical bandgap Eg,Tauc was derived from Tauc plots. Optical constants were determined by spectroscopic ellipsometry measurements in the range between 300 and 1000 nm. It was found that the increase in the CO2 to SiH4 ratio rc not only leads to a higher optical bandgap, but also higher defect density Nd and Urbach energy EU and on the other hand to a lower photoresponse PR. A suitable photoresponse PR = 8.64 × 105 at a high bandgap of Eg,Tauc = 1.91 eV and a defect density of Nd = 1.7 × 1016 cm−3 was achieved. The refraction index and extinction coefficient were lowered with increasing rc. The analysis of light-induced degradation in the (i)a-SiO:H layers showed a smaller increase of deep defects Nd and a higher increase of the Urbach energy EU in terms of the light soaking time with respect to the (i)a-Si:H reference layer

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Section: Discussioncontrasting

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Characterisation of intrinsic silicon oxide absorber layers for use in silicon thin film solar cells

Holinski

Borchert

Hohage

et al. 2015

Phys. Status Solidi A

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“…To further the efficiency, we sought to enhance characteristics of the top cell in terms of open circuit voltage (V oc ) and the response at short-wavelength regions by employing intrinsic amorphous silicon oxide (a-SiO x :H) thin films with wide bandgaps. The a-SiO x :H solar cells delivered better V oc than conventional a-Si:H solar cells [11][12][13][14][15]. However, the efficiency itself was relatively lower than that of a-Si:H cells because of low J sc .…”

Section: Introductionmentioning

confidence: 94%

Light management of a-SiOx:H thin film solar cells with hydrogen-reduced p+ buffer at TiO2/p-layer interface

Kang

Chowdhury

Sichanugrist

et al. 2015

Solar Energy Materials and Solar Cells

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“…Consequently high bandgap amorphous silicon alloys containing carbon, oxygen or both are considered as absorber materials for the top cell. Their single layer properties have been studied for some time [2][3][4][5][6][7][8] and recently their applicability in single and multijunction cells has been confirmed [9][10][11][12][13]]. Yet it is unclear which amorphous silicon alloy is preferable as top cell absorber.…”

Section: Introductionmentioning

confidence: 99%

Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

et al. 2015

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Since solar energy conversion by photovoltaics is most efficient for photon energies at the bandgap of the absorbing material the idea of combining absorber layers with different bandgaps in a multijunction cell has become popular. In silicon thin-film photovoltaics a multijunction stack with more than two subcells requires a high bandgap amorphous silicon alloy top cell absorber to achieve an optimal bandgap combination. We address the question whether amorphous silicon carbide (a-SiC:H) or amorphous silicon oxide (a-SiO:H) is more suited for this type of top cell absorber. Our single cell results show a better performance of amorphous silicon carbide with respect to fill factor and especially open circuit voltage at equivalent Tauc bandgaps. The microstructure factor of single layers indicates less void structure in amorphous silicon carbide than in amorphous silicon oxide. Yet photoconductivity of silicon oxide films seems to be higher which could be explained by the material being not truly intrinsic. On the other hand better cell performance of amorphous silicon carbide absorber layers might be connected to better hole transport in the cell.

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Optimization of an i-a-SiOx:H absorber layer for thin film silicon solar cell applications

Cited by 11 publications

References 14 publications

Characterisation of intrinsic silicon oxide absorber layers for use in silicon thin film solar cells

Characterisation of intrinsic silicon oxide absorber layers for use in silicon thin film solar cells

Light management of a-SiOx:H thin film solar cells with hydrogen-reduced p+ buffer at TiO2/p-layer interface

Comparison of silicon oxide and silicon carbide absorber materials in silicon thin-film solar cells

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