III-V Photodetectors for imaging and single-photon detection in the shortwave infrared

Synopsis

This talk will present NRC's work in advancing III-V photodetector and imaging array technologies for the short-wave infrared (SWIR) and extended SWIR wavelength bands. We have developed SWIR photodetector arrays focusing on decreasing the pixel pitch from 25 µm to 15 and 10 µm and increasing the array format up to 1280 x 1024, using epitaxial growth and Zn diffusion, both performed by MOCVD. These have achieved dark current density <2 nA/cm2 at room temperature and minority carrier diffusion lengths for the InGaAs absorber material are as high as 80 µm. Planar avalanche photodiodes (APD) have been developed using a novel process combining selective area growth and Zn diffusion. The devices show good photo-response uniformity and have been operated in Geiger mode as single photon detectors, at temperatures up to 300 K. These devices achieved an advantageous photon detection efficiency at low excess bias and low dark count rate, and exhibited timing jitter as low as 116 ps FWHM. A novel photodetector for the extended SWIR wavelength band has been developed combining optical absorption enhancement by a plasmonic metasurface with band-to-band absorption in InAs quantum dots (QD) grown in the Stranski-Krastanov mode. While the accumulation of strain limits the number of QD layers that can be grown and therefore the quantum efficiency (QE), the plasmonic metasurface was shown to enhance the QE by a factor of up to 30.

Speaker Bio: Oliver Pitts received the Ph.D. degree in physics from Simon Fraser University in 2004, and conducted postdoctoral research with Simon Fraser University and the University of Wisconsin-Madison on the epitaxial growth of semiconductor materials by MOCVD. In 2009, he joined the Canadian Photonics Fabrication Centre at the National Research Council of Canada (NRC), where he led the development of Zn diffusion processing using the MOCVD reactor. Since 2024, he has been with the Systems Integration and Prototyping Group at NRC, focusing on III-V photodetectors and imaging arrays and their applications.