NASA demonstrates two-dimensional gallium nitride ultraviolet imaging array
Researchers at NASA Goddard Space Flight Center (Greenbelt, MD) developed a two-dimensional gallium nitride (GaN) ultraviolet (UV) imaging array with a matrix of 256 ¥ 256 simple single-element detectors across its surface. As a wide-bandga¥semiconductor, GaN allows visible-blind--that is, insensitive to visible light--detection of UV radiation. The device provides high spatial resolution and sensitivity in the UV spectral range, with little sensitivity in other spectral regions. Thus, instruments can operate in environments with significant visible solar radiation without the need for blocking filters and extensive stray-light baffling.
The array can be operated at room temperature and has demonstrated order-of-magnitude savings in weight, volume, and power demands compared with current UV imaging technology. The array of single-element detectors is indium bump-bonded to a silicon multiplexer that routes the signals from each detector in the array to electronics for measurement and storage. Potential applications of UV array detectors include space-based Earth-imaging platforms, atmospheric platforms, and instrumentation for astronomy.