Polarization-sensitive ultraviolet photodetectors based on M-plane GaN grown on LiAlO2 substrates

Polarization-sensitive photodetectors for the ultraviolet spectral range based on M-plane GaN films grown on LiAlO2 substrates have been fabricated and characterized. These detectors exploit the dichroic properties of strained, M-plane GaN films. For a 400-nm-thick film, a maximum contrast of 7.25 between the detection of light polarized perpendicular and parallel to the c-axis is reached at 363nm. Considerations for the detector design show that thin strained M-plane GaN films will enhance the polarization-sensitive bandwidth, while the maximum contrast can be obtained for relaxed thick films under weak signal detection conditions.