Flexible CMOS electronics based on p-type Ge2Sb2Te5 and n-type InGaZnO4 semiconductors

Ultra-thin p-type chalcogenide glass Ge2Sb2Te5 (GST) semiconductor layers are employed to form flexible thin-film transistors (TFTs). For the first time, TFTs based on GST show saturating output characteristics and an ON/OFF ratio up to 388, exceeding present reports by a factor of ~20. The channel current modulation is greatly enhanced by using ultra-thin 5 nm thick amorphous GST layers and 20 nm thick high-k Al2O3 gate dielectrics. Flexible CMOS circuits are realized in combination with the n-type oxide semiconductor InGaZnO4 (IGZO). The CMOS inverters show voltage gain of up to 69. Furthermore, flexible NAND gates are presented. The bending stability is shown for a tensile radius of 6 mm.