Use of multiple acoustic reflections to enhance SAW UV photo-detector sensitivity

A new approach to enhance the sensitivity of existing SAW UV-visible photo-detectors based on the monitoring of the multiple reflections of the acoustic waves in the Fourier transform of the frequency response (S₂₁) is demonstrated. By using this concept, it is possible to monitor the UV-visible light in a wide intensity range from very high to ultralow. We present a strategy to obtain an ultrafast SAW UV photo-detector with millisecond response by tuning the deposition conditions of the ZnO film and using the multiple-reflections concept. (paper)