Abstract
Nanowire photodetectors are attractive for their high speed and responsivity, enabled by small junction capacitance and high internal gain. However, their effectiveness is hampered by a low quantum efficiency due to poor light coupling to their intrinsically small size. The optically sensitive area can be increased by connecting arrays of standing nanowires (pillars) in parallel under a single readout, but the increase in dark current and total capacitance might reduce pixel sensitivity. The net effect has not yet been thoroughly investigated. In this work, we prove that such multipillar architecture indeed improves effective pixel sensitivity without reducing speed. Our theoretical analysis reveals that the pixel response time is dominated by the constituent nanowires rather than by the global capacitance, resulting in improved quantum efficiency for equivalent speed. We simultaneously characterize different pixel designs on a single focal plane array, demonstrating the viability of multipillar architectures for large-area detectors and imagers.
Original language | English (US) |
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Pages (from-to) | 2280-2286 |
Number of pages | 7 |
Journal | ACS Photonics |
Volume | 9 |
Issue number | 7 |
DOIs | |
State | Published - Jul 20 2022 |
Funding
This work was supported by W. M. Keck Foundation under a Research Grant in Science and Engineering. This work was performed, in part, at the Center for Nanoscale Materials of Argonne National Laboratory. The use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02–06CH11357. S.B. gratefully acknowledges support from the Ryan Fellowship and the International Institute for Nanotechnology at Northwestern University.
Keywords
- collection efficiency
- infrared
- low-dimensional
- nanowires
- photon detectors
- quantum efficiency
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Biotechnology
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering