Flexible and transparent nanocrystal floating gate memory devices using silk protein

•The floating gate memory devices are demonstrated using silk: MWCNT–CdS.•The device has exhibited memory characteristics with a large flatband voltage shift.•The enhancement of memory window with increasing sweeping voltage is observed.•Nearly frequency independent C–V characteristics and memory window is observed.•The memory device is attractive for next-generation flexible bio-electronics.

The charge storage behavior of a floating gate memory device using carbon nanotube-CdS nanostructures embedded in Bombyx mori silk protein matrix has been demonstrated. The capacitance – voltage characteristics in ITO/CNT–CdS-silk composite/Al device exhibits a clockwise hysteresis behavior due to the injection and storage of holes in the quantized valence band energy levels of CdS nanocrystals. The enhanced charge injection resulting in increase in memory window is observed at higher sweeping voltages. Nearly frequency independent hysteresis width over a wide range of 100 kHz–2.0 MHz, indicates its origin due to the charge storage in nanocrystals. The memory behavior of carbon nanotube–CdS nanostructures/silk nanocomposite devices has also been demonstrated on polyethylene terephthalate substrates, which may provide the way for flexible, transparent and printable electronic devices.

Graphical abstractA transparent and flexible floating gate memory device is demonstrated using CdS nanocrystals embedded in silk protein fibroin matrix. The ITO/MWCNT–CdS silk nanocomposite/Al hybrid structure has exhibited memory characteristics with a large flatband voltage shift due to the storage of holes into the CdS nanoparticles decorated on CNT surfaces.Figure optionsDownload full-size imageDownload as PowerPoint slide