Single-Walled carbon nanotubes (SWCNTs) were embedded in hybrid Metal-Insulator-Semiconductor (MIS) memory devices using layer-by-layer (LbL) deposition with polymethylmethacrylate (PMMA) as an organic insulator. It is demonstrated that shortened SWCNTs lead to reliable and large memory windows by virtue of better encapsulation which reduces charge leakage compared with longer SWCNT devices. The capacitance-voltage (C-V) characteristics exhibit a clockwise hysteresis, indicative of electron injection into the SWCNT charge storage elements through the PMMA layer. It is also shown that devices made using sodium dodecyl sulphate (SDS)-based SWCNTs and polyethyleneimine (PEI) produce memory windows larger than 6 V, have a high charge retention of 76% and a storage density better than 2×1012/cm2.