High-performance MoS2 transistors scaled down to 100 nm are studied at various temperatures down to 20 K, where a highest drive current of 800 μA μm(-1) can be achieved. Extremely low electrical noise of 2.8 × 10(-10) μm(2) Hz(-1) at 10 Hz is also achieved at room temperature. Furthermore, a negative differential resistance behavior is experimentally observed and its origin of self-heating is identified using pulsed-current-voltage measurements.

We showed here that red light can be used to tune the self-assembly of amphiphilic diselenide-containing block copolymers, via the production of singlet oxygen in the presence of chromophores such as porphyrin derivatives. Furthermore, red light can be used to trigger the release of encapsulated cargo in polymeric micelles.

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Because of their wide bandgap and ultrathin body properties, two-dimensional materials are currently being pursued for next-generation electronic and optoelectronic applications. Although there have been increasing numbers of studies on improving the performance of MoS field-effect transistors (FETs) using various methods, the dielectric interface, which plays a decisive role in determining the mobility, interface traps, and thermal transport of MoS FETs, has not been well explored and understood. In this article, we present a comprehensive experimental study on the effect of high-k dielectrics on the performance of few-layer MoS FETs from 300 to 4.3 K. Results show that AlO/HfO could boost the mobility and drain current. Meanwhile, MoS transistors with AlO/HfO demonstrate a 2× reduction in oxide trap density compared to that of the devices with the conventional SiO substrate. Also, we observe a negative differential resistance effect on the device with 1 μm-channel length when using conventional SiO as the gate dielectric due to self-heating, and this is effectively eliminated by using the AlO/HfO gate dielectric. This dielectric engineering provides a highly viable route to realizing high-performance transition metal dichalcogenide-based FETs.

Transition metal dichalcogenides (TMDCs) are emerging two-dimensional materials for their potential in next-generation electronics. One of the big challenges is to realize a large single-crystal TMDCs film with high mobility, which is critical for channel materials. Herein, we report an optimized atmospheric pressure chemical vapor deposition method for growing large single-crystal monolayer MoS2 on molten glass substrate with domain size up to 563 μm. Better interface quality can be achieved using high-κ dielectrics with respect to the conventional thermal SiO2. Mobility up to 24 cm2 V−1 s−1 at room temperature and 84 cm2 V−1 s−1 at 20 K can be obtained. This low-cost growth of high-quality, large single-crystal size of two dimensional materials provides a pathway for high-performance two dimensional electronic devices.

a great challenge for top-gate RF device fabrication since atomic layer deposition (ALD) typically needs oxygen or water as precursor. [13][14][15] Even though recent research progress of capping BP with ALD high-κ dielectrics shows effective suppression of the black phosphorus surface oxidation, [16][17][18] this process still degrades the electric performance of BP transistors compared with the back-gate devices with minimal exposure to precursors. [19] As shown in previous studies, electric performance of BP FETs can be dominated by the channel dielectric interface where ALD high-κ dielectrics performs better than conventional SiO 2 . For instance, backgate BP transistors on high-κ substrate exhibit improved device performance in comparison with BP FETs on conventional SiO 2 . [11,20] Also, encapsulation by hexagonal boron nitride results in great enhancement of the hole mobility of BP. [6,21,22] However, this approach requires multiple dry transfer steps for both black phosphorus and hexagonal boron nitride flakes with precise alignment for a single device, and thus it has extremely low throughput and yield.In this paper, we report a new approach toward high-performance BP RF transistors using a Damascene-like planarization process to create an embedded gate stack with high-κ dielectrics, which enables high-quality interface while avoids the precursor exposure to the BP channel surface at the same time. [23,24] Side-by-side comparison with two conventional topgate structures shows at least twice improvement in the radio frequency performance of the embedded gate devices. Systematic studies of the radio frequency performance from room temperature down to 20 K are carried out for the first time.A record high extrinsic f max of 17 and 31 GHz for the device with 400 nm gate length has been achieved at room temperature and 20 K, respectively. The ratio of f max /f T has been improved to over two, a twice improvement over previous results, showing a significant advantage in power gains compared with graphene transistors. [23,24]

We have prepared a UV-responsive polymeric superamphiphile, formed by a malachite green derivative and the double hydrophilic block copolymer methoxy-poly(ethylene glycol)(114)-block-poly(l-lysine hydrochloride)(200) (PEG-b-PLKC) on the basis of electrostatic interactions. The malachite green derivative undergoes photo-ionization upon UV irradiation, which makes it more hydrophilic, resulting in changes in the self-assembly behavior of the polymeric superamphiphile. For this reason, the polymeric superamphiphile originally self-assembles to form sheetlike aggregates, which disassemble after UV irradiation because of the increased solubility of the malachite green derivative. By use of Nile red as a probe, the polarity of the polymeric superamphiphile solution is confirmed to be increased after UV irradiation by fluorescence spectra, which also explains the disassembly of the polymeric superamphiphile.