Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Jun 7;29(12):19024-19033.
doi: 10.1364/OE.421857.

Avalanche photodetectors with photon trapping structures for biomedical imaging applications

Cesar Bartolo-Perez, Soroush Chandiparsi, Ahmed S Mayet, Hilal Cansizoglu, Yang Gao, Wayesh Qarony, Ahasan AhAmed, Shih-Yuan Wang, Simon R Cherry, M Saif Islam, Gerard Ariño-Estrada

Avalanche photodetectors with photon trapping structures for biomedical imaging applications

Cesar Bartolo-Perez et al. Opt Express. .

Abstract

Enhancing photon detection efficiency and time resolution in photodetectors in the entire visible range is critical to improve the image quality of time-of-flight (TOF)-based imaging systems and fluorescence lifetime imaging (FLIM). In this work, we evaluate the gain, detection efficiency, and timing performance of avalanche photodiodes (APD) with photon trapping nanostructures for photons with 450 nm and 850 nm wavelengths. At 850 nm wavelength, our photon trapping avalanche photodiodes showed 30 times higher gain, an increase from 16% to >60% enhanced absorption efficiency, and a 50% reduction in the full width at half maximum (FWHM) pulse response time close to the breakdown voltage. At 450 nm wavelength, the external quantum efficiency increased from 54% to 82%, while the gain was enhanced more than 20-fold. Therefore, silicon APDs with photon trapping structures exhibited a dramatic increase in absorption compared to control devices. Results suggest very thin devices with fast timing properties and high absorption between the near-ultraviolet and the near infrared region can be manufactured for high-speed applications in biomedical imaging. This study paves the way towards obtaining single photon detectors with photon trapping structures with gains above 106 for the entire visible range.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Fig. 1.
Fig. 1.
Representation of the absorption and electric field profiles of two APD configurations. (a) Conventional APD (Control), and (b) Photon trapping APD (PT APD).
Fig. 2.
Fig. 2.
(a) SEM image of control (left) and photon trapping (right) device. (b) Measured doping profile of the photodetectors.
Fig. 3.
Fig. 3.
Optical and electrical simulations in Si APD at 850 nm wavelength. Power absorption in (a) control Si PD and (b) PT-silicon PD. (c) Electric field profile of the fabricated device.
Fig. 4.
Fig. 4.
Current-voltage and gain for Si APD. (a) I-V characteristics of control and photon trapping (PT) devices. (b) Multiplication gain of PT and control device.
Fig. 5.
Fig. 5.
Pulse time response for Si PD under the three regimes of operation PIN (pink) APD (green) and SPAD (red), for the (a) control and (b) Photon Trapping PD.
Fig. 6.
Fig. 6.
FDTD simulations of 2.5 µm-thick APDs with input light of 450 nm for (a) a control APD and (b) a photon trapping APD. Inset figure is an SEM image. (c) Experimental gain measurements of fabricated devices at 450 nm wavelength.
Fig. 7.
Fig. 7.
Absorption control in photon trapping PD at 450 nm wavelength. Simulated power absorption profile of (a) control and (b) photon trapping PD with 1.2 µm thick silicon. Our photon trapping PDs with such a thin absorber layer exhibit more than 90% absorption. (c) Influence of period and diameter of the photon trapping nanostructures in power absorption at 450 nm wavelength. (d) Cumulative absorption in control (blue) and PT (red) silicon SPAD. Overlap of electric field profile of a PD with a pπpn structure with the absorption of light for optical generation, for higher gain and lower noise avalanche-based PD. (e) Influence of diameter in cylindrical photon trapping structure at broadband range of wavelengths. (f) Comparison of absorption at a broadband range of wavelengths between cylindrical and inverted pyramid structure.
See this image and copyright information in PMC

References

    1. Hadfield R. H., “Single-photon detectors for optical quantum information applications,” Nat. Photonics 3(12), 696–705 (2009).10.1038/nphoton.2009.230 - DOI
    1. Chesi G., Malinverno L., Allevi A., Santoro R., Caccia M., Martemiyanov A., Bondani M., “Optimizing Silicon photomultipliers for Quantum Optics,” Sci. Rep. 9(1), 7433 (2019).10.1038/s41598-019-43742-1 - DOI - PMC - PubMed
    1. Fan-Yuan G.-J., Teng J., Wang S., Yin Z.-Q., Chen W., He D.-Y., Guo G.-C., Han Z.-F., “Optimizing Single-Photon Avalanche Photodiodes for Dynamic Quantum Key Distribution Networks,” Phys. Rev. Appl. 13(5), 054027 (2020).10.1103/PhysRevApplied.13.054027 - DOI
    1. Zhang C., Lindner S., Antolović I. M., Pavia J. M., Wolf M., Charbon E., “A 30-frames/s, 252 ( 144 SPAD Flash LiDAR With 1728 Dual-Clock 48.8-ps TDCs, and Pixel-Wise Integrated Histogramming,” IEEE J. Solid-State Circuits 54(4), 1137–1151 (2019).10.1109/JSSC.2018.2883720 - DOI
    1. Ximenes A. R., Padmanabhan P., Lee M., Yamashita Y., Yaung D. N., Charbon E., “A 256×256 45/65 nm 3D-stacked SPAD-based direct TOF image sensor for LiDAR applications with optical polar modulation for up to 18.6 dB interference suppression,” in 2018 IEEE International Solid - State Circuits Conference - (ISSCC), 2018), 96–98.