Avalanche photodetectors with photon trapping structures for biomedical imaging applications

• DOI: 10.1364/oe.421857
• Publication Date: 2021-04-27T03:30:20Z
• Authors: 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
• Keywords: Diagnostic Imaging; Silicon; FOS: Physical sciences; Bioengineering; Optical Physics; 02 engineering and technology; Applied Physics (physics.app-ph); 530; Atomic; 7. Clean energy; 01 natural sciences; Engineering; 0103 physical sciences; FOS: Electrical engineering, electronic engineering, information engineering; Nanotechnology; Humans; Electrical and Electronic Engineering; molecular and optical physics; sensors and digital hardware; Communications Technologies; Photons; Image and Video Processing (eess.IV); 500; Optics; Physics - Applied Physics; Equipment Design; Electrical Engineering and Systems Science - Image and Video Processing; Physical Sciences; Electronics; 0210 nano-technology; Communications engineering; Physics - Optics; Optics (physics.optics)

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.