Black Phosphorus p-MOSFETs with High Transconductance and Nearly Ideal Subthreshold Slope

We report record performance for black phosphorus p-MOSFETs. The devices have locally patterned back gates and 20-nm-thick HfO2 gate dielectrics. Devices with effective gate length, Leff = 1.0 um display extrinsic transconductance, gm, of 101 uS/um at a drain-to-source bias voltage, Vds = -3 V. Temperature-dependent analysis also shows that the subthreshold slope, SS, is nearly ideal, with a minimum value of SS = 66 mV/decade at room temperature and Vds = -0.1 V. Furthermore, devices with 7-nm HfO2 dielectrics and Leff = 0.3 um displayed gm as high as 204 uS/um at Vds = -1.5 V.