Solution processed bilayer junction of silk fibroin and semiconductor quantum dots as multilevel memristor devices

摘要

Silkworm protein is integrated with semiconductor quantum dots (CdSe) to form bi-layer electrical memory devices. These films are individually spin coated on ITO surface to form ITO-silk fibroin:CdSe-metal junctions. These materials are characterized by DSC, TGA, FT1R, UV-visible absorbance, X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) and TEM to understand their physical properties. The charge transport is carried out on the above devices by cyclic voltage scan in the sequence zero-positive-zero-negative-zero to study their electrical memory switching behavior. Devices exhibit multilevel electrical switching both in the forward and in the reverse regions that are quite symmetric, the ON/OFF ratios are well resolved. These junctions posses a high repeatability with a good endurance and hence can be important interfaces for electrical information storage applications. The observed results of the above memristors are explained in terms of their energy band diagram, it is observed that in these interfaces monopolar charge transport of holes is the dominant mechanism that is further supported by multiple hole trapping centers both in CdSe and silk fibroin energy gaps.