Thin-film a-Si/c-Si1-xGex/c-Si heterojunction solar cells: Design and material quality requirements

Sabina Abdul Hadi; Pouya Hashemi; Ammar Nayfeh; Judy L. Hoyt

doi:10.1149/1.3628603

Thin-film a-Si/c-Si_1-xGe_x/c-Si heterojunction solar cells: Design and material quality requirements

Sabina Abdul Hadi
, Pouya Hashemi
, Ammar Nayfeh
, Judy L. Hoyt

Electrical Engineering

Massachusetts Institute of Technology

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

31 Scopus citations

Abstract

a-Si:H/crystalline-Si_1-xGe_x/c-Si heterojunction solar cells (HIT cells) are simulated and fabricated for the first time. Cells with junction layers consisting of Si, Si_0.75Ge_0.25, and Si_0.59Ge_0.41 are compared to study the effect of increasing Ge concentration. The results show a V_oc drop from 0.6V for Si cells to 0.4V for Si_0.59Ge_0.41, consistent with the reduction in bandgap. The measured J_sc increases from ∼18.5 mA/cm² for Si cells to 20.3 mA/cm² for the Si _0.59Ge_0.41 cells, for one light pass. Simulations suggest that the measured J_sc for the Si_0.59Ge_0.41 based solar cells is limited by a low lifetime. In order for Si _1-xGe_x based cells to exceed the efficiency of Si, simulations indicate that Ge percentages larger than 40% and lifetimes above 1 μs are required.

Original language	British English
Title of host publication	Photovoltaics for the 21st Century 7
Pages	3-14
Number of pages	12
Edition	4
ISBN (Electronic)	9781607682585
DOIs	https://doi.org/10.1149/1.3628603
State	Published - 2011
Event	Photovoltaics for the 21st Century 7 - 220th ECS Meeting - Boston, MA, United States Duration: 9 Oct 2011 → 14 Oct 2011

Publication series

Name	ECS Transactions
Number	4
Volume	41
ISSN (Print)	1938-5862
ISSN (Electronic)	1938-6737

Conference

Conference	Photovoltaics for the 21st Century 7 - 220th ECS Meeting
Country/Territory	United States
City	Boston, MA
Period	9/10/11 → 14/10/11

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1149/1.3628603

Cite this

@inproceedings{ae2bf793e9134418a68c83683b408be2,

title = "Thin-film a-Si/c-Si1-xGex/c-Si heterojunction solar cells: Design and material quality requirements",

abstract = "a-Si:H/crystalline-Si1-xGex/c-Si heterojunction solar cells (HIT cells) are simulated and fabricated for the first time. Cells with junction layers consisting of Si, Si0.75Ge0.25, and Si0.59Ge0.41 are compared to study the effect of increasing Ge concentration. The results show a Voc drop from 0.6V for Si cells to 0.4V for Si0.59Ge0.41, consistent with the reduction in bandgap. The measured Jsc increases from ∼18.5 mA/cm2 for Si cells to 20.3 mA/cm2 for the Si 0.59Ge0.41 cells, for one light pass. Simulations suggest that the measured Jsc for the Si0.59Ge0.41 based solar cells is limited by a low lifetime. In order for Si 1-xGex based cells to exceed the efficiency of Si, simulations indicate that Ge percentages larger than 40\% and lifetimes above 1 μs are required.",

author = "Hadi, \{Sabina Abdul\} and Pouya Hashemi and Ammar Nayfeh and Hoyt, \{Judy L.\}",

year = "2011",

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isbn = "9781566779043",

series = "ECS Transactions",

number = "4",

pages = "3--14",

booktitle = "Photovoltaics for the 21st Century 7",

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note = "Photovoltaics for the 21st Century 7 - 220th ECS Meeting ; Conference date: 09-10-2011 Through 14-10-2011",

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TY - GEN

T1 - Thin-film a-Si/c-Si1-xGex/c-Si heterojunction solar cells

T2 - Photovoltaics for the 21st Century 7 - 220th ECS Meeting

AU - Hadi, Sabina Abdul

AU - Hashemi, Pouya

AU - Nayfeh, Ammar

AU - Hoyt, Judy L.

PY - 2011

Y1 - 2011

N2 - a-Si:H/crystalline-Si1-xGex/c-Si heterojunction solar cells (HIT cells) are simulated and fabricated for the first time. Cells with junction layers consisting of Si, Si0.75Ge0.25, and Si0.59Ge0.41 are compared to study the effect of increasing Ge concentration. The results show a Voc drop from 0.6V for Si cells to 0.4V for Si0.59Ge0.41, consistent with the reduction in bandgap. The measured Jsc increases from ∼18.5 mA/cm2 for Si cells to 20.3 mA/cm2 for the Si 0.59Ge0.41 cells, for one light pass. Simulations suggest that the measured Jsc for the Si0.59Ge0.41 based solar cells is limited by a low lifetime. In order for Si 1-xGex based cells to exceed the efficiency of Si, simulations indicate that Ge percentages larger than 40% and lifetimes above 1 μs are required.

AB - a-Si:H/crystalline-Si1-xGex/c-Si heterojunction solar cells (HIT cells) are simulated and fabricated for the first time. Cells with junction layers consisting of Si, Si0.75Ge0.25, and Si0.59Ge0.41 are compared to study the effect of increasing Ge concentration. The results show a Voc drop from 0.6V for Si cells to 0.4V for Si0.59Ge0.41, consistent with the reduction in bandgap. The measured Jsc increases from ∼18.5 mA/cm2 for Si cells to 20.3 mA/cm2 for the Si 0.59Ge0.41 cells, for one light pass. Simulations suggest that the measured Jsc for the Si0.59Ge0.41 based solar cells is limited by a low lifetime. In order for Si 1-xGex based cells to exceed the efficiency of Si, simulations indicate that Ge percentages larger than 40% and lifetimes above 1 μs are required.

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