We demonstrated ultra-thin-body (UTB) junctionless (JL) p-type field-effect transistors (pFETs) on Si using GaAs channels. Wafer bonding and epitaxial lift-off techniques were employed to fabricate the UTB p-GaAs-on-insulator on a Si template. Subsequently, we evaluated the JL FETs having different p-GaAs channel thicknesses considering both maximum depletion width and doping concentration for high performance. Furthermore, by introducing a double-gate operation, we more effectively controlled threshold voltage and attained an even higher I-ON/I-OFF of > 10(6), as well as a low subthreshold swing value of 300 mV/dec. (c) 2018 Author(s).