The proposed device is capable of counting ultraviolet (UV) photons, is compatible for inclusion into space instruments, and has applications as deep-UV detectors for calibration systems, curing systems, and crack detection. The device is based on a Separate Absorption and Charge Multiplication (SACM) structure. It is based on aluminum gallium nitride (AlGaN) absorber on a silicon carbide APD (avalanche photodiode). The AlGaN layer absorbs incident UV photons and injects photo-generated carriers into an underlying SiC APD that is operated in Geiger mode and provides current multiplication via avalanche breakdown.

The solid-state detector is capable of sensing 100-to-365-nanometer wavelength radiation at a flux level as low as 6 photons/pixel/s. Advantages include, visible-light blindness, operation in harsh environments (e.g., high temperatures), deep-UV detection response, high gain, and Geiger mode operation at low voltage. Furthermore, the device can also be designed in array formats, e.g., linear arrays or 2D arrays (micropixels inside a superpixel).

This work was done by Shahid Aslam, Federico A. Herrero, and John Sigwarth of Goddard Space Flight Center and Neil Goldsman and Akin Akturk of The University of Maryland. For more information, download the Technical Support Package (free white paper) at under the Physical Sciences category. GSC-15604-1

Photonics Tech Briefs Magazine

This article first appeared in the September, 2010 issue of Photonics Tech Briefs Magazine.

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