Heterostructure of TiO2 and macroporous silicon: The simplest relaxation oscillator

A heterostructure composed of TiO2 and macroporous silicon in this study may represent the simplest relaxation oscillator ever reported. It consisted of macroporous Si with TiO2 grown on its pore walls, and metallic contacts. This is also the first relaxation oscillator of its kind. Such oscillators are commonly formed by a capacitor or an inductor and a feedback loop with a switching device operating with a threshold voltage. The dielectric characteristics of TiO2 (capacitive behavior) in combination with the tunnel diode characteristics of the heterostructure (presenting a negative differential resistance, when activated at a threshold voltage) are shown to give rise to the relaxation oscillations. (C) 2021 The Authors. Publishing services by Elsevier B.V. on behalf of Vietnam National University, Hanoi.