The com bination of mixed-dimensional semiconducti ng materials can provide additional freedom to construct integrated n anoscale electronic and optoelectronic devices with diverse functionalities. In this work, we re...The com bination of mixed-dimensional semiconducti ng materials can provide additional freedom to construct integrated n anoscale electronic and optoelectronic devices with diverse functionalities. In this work, we report a high-performanee dual-channel phototransistor based on one-dimensional (1D)/two-dimensional (2D) trigonal selenium (t-Se)/ReS2 heterostructures grown by chemical vapor deposition. The injection and separati on efficie ncy of photoge nerated electro n-hole pairs can be greatly improved due to the high-quality in terfacial con tact betwee n t-Se nano belts and ReS2 films. Compared with bare ReS2 film devices, the dual-cha nnel phototra nsistor based on t-Se/ReS2 heterostructure exhibits considerable enhancement with the responsivity (R) and detectivity (D^*) up to 98 A·W^-1 and 6 x 10^10 Jones at 400 nm illumination with an in tensity of 1.7 mW·cm^-2, respectively. Besides, the respo nse time can also be reduced by three times of magnitude to less than 50 ms due to the type-11 band alignment at the in terface. This study opens up a promising ave nue for high-performa nee photodetectors by constructing mixed-dimensional heterostructures.展开更多
This paper introduces the first tunable ferroelectric capacitor(FeCAP)-based unreleased RF MEMS resonator,integrated seamlessly in Texas Instruments’130 nm Ferroelectric RAM(FeRAM)technology.The designs presented her...This paper introduces the first tunable ferroelectric capacitor(FeCAP)-based unreleased RF MEMS resonator,integrated seamlessly in Texas Instruments’130 nm Ferroelectric RAM(FeRAM)technology.The designs presented here are monolithically integrated in solid-state CMOS technology,with no post-processing or release step typical of other MEMS devices.An array of FeCAPs in this complementary metal-oxide-semiconductor(CMOS)technology’s back-end-of-line(BEOL)process were used to define the acoustic resonance cavity as well as the electromechanical transducers.To achieve high quality factor(Q)of the resonator,acoustic waveguiding for vertical confinement within the CMOS stack is studied and optimized.Additional design considerations are discussed to obtain lateral confinement and suppression of spurious modes.An FeCAP resonator is demonstrated with fundamental resonance at 703 MHz and Q of 1012.This gives a frequency-quality factor product f·Q=7:11×10^(11) which is 1.6×higher than the most state-of-the-art Pb(Zr,Ti)O_(3)(PZT)resonators.Due to the ferroelectric characteristics of the FeCAPs,transduction of the resonator can be switched on and off by adjusting the electric polarization.In this case,the resonance can be turned off completely at±0.3 V corresponding to the coercive voltage of the constituent FeCAP transducers.These novel switchable resonators may have promising applications in on-chip timing,ad-hoc radio front ends,and chip-scale sensors.展开更多
基金National Natural Science Foundation of China (Nos. 51572057 and 51772064)AFOSR/NSF EFRI 2DARE program, ARO and SRC.
文摘The com bination of mixed-dimensional semiconducti ng materials can provide additional freedom to construct integrated n anoscale electronic and optoelectronic devices with diverse functionalities. In this work, we report a high-performanee dual-channel phototransistor based on one-dimensional (1D)/two-dimensional (2D) trigonal selenium (t-Se)/ReS2 heterostructures grown by chemical vapor deposition. The injection and separati on efficie ncy of photoge nerated electro n-hole pairs can be greatly improved due to the high-quality in terfacial con tact betwee n t-Se nano belts and ReS2 films. Compared with bare ReS2 film devices, the dual-cha nnel phototra nsistor based on t-Se/ReS2 heterostructure exhibits considerable enhancement with the responsivity (R) and detectivity (D^*) up to 98 A·W^-1 and 6 x 10^10 Jones at 400 nm illumination with an in tensity of 1.7 mW·cm^-2, respectively. Besides, the respo nse time can also be reduced by three times of magnitude to less than 50 ms due to the type-11 band alignment at the in terface. This study opens up a promising ave nue for high-performa nee photodetectors by constructing mixed-dimensional heterostructures.
基金This work was funded by the DARPA MTO UPSIDE program.
文摘This paper introduces the first tunable ferroelectric capacitor(FeCAP)-based unreleased RF MEMS resonator,integrated seamlessly in Texas Instruments’130 nm Ferroelectric RAM(FeRAM)technology.The designs presented here are monolithically integrated in solid-state CMOS technology,with no post-processing or release step typical of other MEMS devices.An array of FeCAPs in this complementary metal-oxide-semiconductor(CMOS)technology’s back-end-of-line(BEOL)process were used to define the acoustic resonance cavity as well as the electromechanical transducers.To achieve high quality factor(Q)of the resonator,acoustic waveguiding for vertical confinement within the CMOS stack is studied and optimized.Additional design considerations are discussed to obtain lateral confinement and suppression of spurious modes.An FeCAP resonator is demonstrated with fundamental resonance at 703 MHz and Q of 1012.This gives a frequency-quality factor product f·Q=7:11×10^(11) which is 1.6×higher than the most state-of-the-art Pb(Zr,Ti)O_(3)(PZT)resonators.Due to the ferroelectric characteristics of the FeCAPs,transduction of the resonator can be switched on and off by adjusting the electric polarization.In this case,the resonance can be turned off completely at±0.3 V corresponding to the coercive voltage of the constituent FeCAP transducers.These novel switchable resonators may have promising applications in on-chip timing,ad-hoc radio front ends,and chip-scale sensors.
