Excellent Responsivity and Low Dark Current Obtained with Metal-Assisted Chemical Etched Si Photodiode

Metal-assisted chemical etched (MACE, also known as MacEtch or MCCE) nanostructures are utilized widely in the solar cell industry due to their excellent optical properties combined with a simple and cost-efficient fabrication process. The photodetection community, on the other hand, has not shown m...

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Bibliographic Details
Published in:IEEE sensors journal 2023-04, Vol.23 (7), p.1-1
Main Authors: Chen, Kexun, Setala, Olli E., Liu, Xiaolong, Radfar, Behrad, Pasanen, Toni P., Serue, Michael D., Heinonen, Juha, Savin, Hele, Vahanissi, Ville
Format: Article
Language:English
Subjects:
Aluminum oxide
Dark current
MACE
Nanostructure
Nanostructures
Optical properties
Optical surface waves
Passivity
photodetector
Photodiodes
Photovoltaic cells
Quantum efficiency
Radiative recombination
responsivity
Silicon
Solar cells
Surface waves
Thin films
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Summary:Metal-assisted chemical etched (MACE, also known as MacEtch or MCCE) nanostructures are utilized widely in the solar cell industry due to their excellent optical properties combined with a simple and cost-efficient fabrication process. The photodetection community, on the other hand, has not shown much interest towards MACE due to its drawbacks including insufficient surface passivation, increased junction recombination, and possible metal contamination, which are especially detrimental to pn-photodiodes. Here, we aim to change this by demonstrating how to fabricate high-performance MACE pn-photodiodes with above 90% external quantum efficiency (EQE) without external bias voltage at 200-1000 nm and dark current less than 3 nA/cm 2 at -5 V using industrially applicable methods. The key is to utilize an induced junction created by an atomic layer deposited highly charged Al 2 O 3 thin film that simultaneously provides efficient field-effect passivation and full conformality over the MACE nanostructures. Achieving close to ideal performance demonstrates the vast potential of MACE nanostructures in the fabrication of high-performance low-cost pn-photodiodes.
ISSN:1530-437X
1558-1748
DOI:10.1109/JSEN.2023.3246505