Effects of Amorphous Silicon Thickness Variation on Infrared-Tuned Silicon Heterojunction Bottom Cells

Jianwei Shi, Zhengshan J. Yu, Ashling Mehdi Leilaeioun, Kathryn Fisher, Zachary C. Holman

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


Silicon-based tandem cells are promising to surpass the 29.4% efficiency limit of single-junction silicon solar cells. Silicon heterojunction (SHJ) solar cells are an excellent choice for the bottom cell in tandems because of their record-high open-circuit voltage and excellent spectral efficiency at near-infrared wavelengths. However, the hydrogenated amorphous silicon (aSi:H) properties of SHJ cells have not been optimized for tandem applications. In this work, we vary the front intrinsic and doped a-Si:H layer thicknesses in SHJ cells to study device performance under full-spectrum (300-1200 nm) and infrared-spectrum (700-1200 nm) illumination. We find that the design rules for the front a-Si:H layer stack are surprisingly similar in both cases, but the SHJ cell efficiency variance greatly decreases - by a factor of 3 to 4 - when changing from full-spectrum to infrared-spectrum illumination. That is, cells with substantial a-Si:H thickness variation have narrow efficiency and current distributions when used as bottom cells, which is desirable for subsequent tandem solar module integration. From a manufacturing perspective, there is no need to make additional a-Si:H adjustments specifically for bottom cells, and much higher a-Si:H thickness non-uniformity can be tolerated, which may allow for cheaper deposition tools.

Original languageEnglish (US)
Title of host publication2019 IEEE 46th Photovoltaic Specialists Conference, PVSC 2019
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages6
ISBN (Electronic)9781728104942
StatePublished - Jun 2019
Event46th IEEE Photovoltaic Specialists Conference, PVSC 2019 - Chicago, United States
Duration: Jun 16 2019Jun 21 2019

Publication series

NameConference Record of the IEEE Photovoltaic Specialists Conference
ISSN (Print)0160-8371


Conference46th IEEE Photovoltaic Specialists Conference, PVSC 2019
Country/TerritoryUnited States


  • amorphous silicon
  • heterojunction
  • infrared
  • solar cell
  • tandem

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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