NOVEL PIEZOELECTRIC-BARRIER HETEROSTRUCTURE FOR ALL-OPTICAL LIGHT-MODULATION

We propose a novel quantum heterostructure especially designed to be u sed as an optically-controlled light modulator device with moderate op tical power densities and without the need of electrical contacts. The device exploits the piezoelectric effect in strained semiconductor la yers and its principle relies on the fact that upon optical excitation , a substantial space charge field perpendicular to the quantum well p lane is established in every period of the heterostructure, owing to e fficient photocarrier separation in piezoelectric barrier layers. We p resent preliminary results which demonstrate a photo-induced electric field of more than 30 kV/cm with about 100 W/cm(2) inducing large spec tral shifts in the photoluminescence spectra of a CdHgTe quantum well. (C) 1997 Elsevier Science Ltd.