A Feasible Approach to Optical--Electrical Hybrid Data Storage Using Phase Change Material

We present our experimental results supporting optical--electrical hybrid data storage by optical recording and electrical reading using Ge₂Sb₂Te₅as recording medium. The sheet resistance of laser-irradiated Ge₂Sb₂Te₅ films exhibits an abrupt change of four orders of magnitude (from 10⁷ to 10³Ω/sq) with increasing laser power, current-voltage curves of the amorphous area and the laser-crystallized dots, measured by a conductive atomic force microscope (C-AFM), show that their resistivities are 2.725 and 3.375×10^-3Ω, respectively, the surface current distribution in the films also shows high and low resistance states. All these results suggest that the laser-recorded bit can be read electrically by measuring the change of electrical resistivity, thus making optical--electrical hybrid data storage possible.