Development of efficient broadband digital acoustic device based on nanocrystalline silicon ultrasound emitter

There is an extremely high contrast in the thermal properties between single-crystalline silicon and quantum-sized nanocrystalline silicon. As previously reported, it makes possible to generate acoustic wave only by thermal transfer without any mechanical surface vibration systems. To make the best use of its characteristics, a digital drive scheme is introduced into a two-dimensionally arrayed device. Significant output amplitude is observed throughout the frequency of audio to ultrasonic band. This result provides technology platform for digital acoustic applications.