The negative capacitance (NC) Ge pFETs with different thicknesses of HfZrO<sub>x</sub> (HZO) are investigated. Although NC transistors with 6.6 nm HZO exhibit a 56 mV/decade subthreshold swing, the hysteresis inevitably occurs. The hysteresis-free characteristics are demonstrated in NC Ge pFETs with 4.5 and 3.7 nm HZO. We also study the impact of annealing temperature on the electrical performance of devices, which shows that the hysteresis reduces with the increasing of annealing temperature. By tuning the parameters of HZO, the NC devices achieve better SS and on-current in comparison with the control transistors.
We compare optical characteristics of black phosphorus photodetectors integrated with a stripe waveguide and a ridge waveguide by optical field intensity and absorption spectrum, which proves that the stripe waveguide is better for enhancing the optical absorption of black phosphorus photodetector. The strain effect on the band structure of black phosphorus is investigated using the first-principles method based on density functional theory (DFT). The band structure of 5-layer BP experiences a direct-indirect-direct transition and a semiconductor-metal transition (SMT) when applied different strains. As a result, the cut-off wavelength and the responsivity of this strained BP photodetector can reach 3.76μm and 0.48 A/W respectively. In a word, the waveguide-integrated black phosphorus photodetector under strain for mid-infrared range may promote potential novel optoelectronic device applications based on two-dimensional materials in the future.
Conference Committee Involvement (1)
6th annual Sino-French “Photonics and Optoelectronics” PHOTONET International Research Network Workshop