Growth and Fabrication of GaAs Thin-Film Solar Cells on a Si Substrate via Hetero Epitaxial Lift-Off

We demonstrate, for the first time, GaAs thin film solar cells epitaxially grown on a Si substrate using a metal wafer bonding and epitaxial lift-off process. A relatively thin 2.1 μm GaAs buffer layer was first grown on Si as a virtual substrate, and a threading dislocation density of 1.8 × 10<s...

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Bibliographic Details
Published in:Applied Sciences
Main Authors: Seungwan Woo, Geunhwan Ryu, Taesoo Kim, Namgi Hong, Jae-Hoon Han, Rafael Jumar Chu, Jinho Bae, Jihyun Kim, In-Hwan Lee, Deahwan Jung, Won Jun Choi
Format: Article
Language:English
Published: MDPI AG 2022-01-01
Subjects:
solar cell
flexible photovoltaics
wafer bonding
epitaxial lift-off
heteroepitaxial growth
Online Access:https://www.mdpi.com/2076-3417/12/2/820
Description
Summary:We demonstrate, for the first time, GaAs thin film solar cells epitaxially grown on a Si substrate using a metal wafer bonding and epitaxial lift-off process. A relatively thin 2.1 μm GaAs buffer layer was first grown on Si as a virtual substrate, and a threading dislocation density of 1.8 × 10<sup>7</sup> cm<sup>−2</sup> was achieved via two In<sub>0.1</sub>Ga<sub>0.9</sub>As strained insertion layers and 6× thermal cycle annealing. An inverted p-on-n GaAs solar cell structure grown on the GaAs/Si virtual substrate showed homogenous photoluminescence peak intensities throughout the 2″ wafer. We show a 10.6% efficient GaAs thin film solar cell without anti-reflection coatings and compare it to nominally identical upright structure solar cells grown on GaAs and Si. This work paves the way for large-scale and low-cost wafer-bonded III-V multi-junction solar cells.
ISSN:2076-3417

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