Key Laboratory for the Physics and Chemistry of Nanodevices

Electronics, China

Key Laboratory for the Physics and Chemistry of Nanodevices

Electronics, China
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Liang S.,Key Laboratory for the Physics and Chemistry of Nanodevices | Wei N.,Key Laboratory for the Physics and Chemistry of Nanodevices | Ma Z.,Key Laboratory for the Physics and Chemistry of Nanodevices | Wang F.,Key Laboratory for the Physics and Chemistry of Nanodevices | And 4 more authors.
ACS Photonics | Year: 2017

Applied as on-chip infrared light sources for future nanophotonic circuits and information optoelectronics, light emitters should show a narrow spectral width, strong emission, low onset voltage, and better tunability of light output to an external drive. Here, by utilizing small-diameter (d < 1 nm) chirality-sorted (8,3) and (8,4) carbon nanotube (CNT) films and their charged exciton (trions) electroluminescence (EL), we achieve performance improvements via channel length (Lch) scaling. With a short Lch, the devices can show better emission, and the external EL efficiency (nEL) in free space can reach ∼6 × 10-4 (that is obtained at a current of ∼5-8 mA and a voltage of ∼4-6 V from the 0.5-μm-channel device, and the corresponding current density is ∼1700-3000 A cm-2). The strong emission at smaller bias gives CNT-based emitters a wider optoelectronic compatibility with other nanomaterial systems. Furthermore, by an integration of the emitter with a λ/2 optical cavity, cavity-controlled well-defined light output can be achieved, with narrow spectral widths at selectable emission windows (e.g., ∼28 meV at a wavelength of 1180 nm). The results show possible applications of chirality-sorted CNT film light emitters for further on-chip nanophotonic systems. © 2017 American Chemical Society.


Wang Z.,Key Laboratory for the Physics and Chemistry of Nanodevices | Ding L.,Key Laboratory for the Physics and Chemistry of Nanodevices | Pei T.,Key Laboratory for the Physics and Chemistry of Nanodevices | Zhang Z.,Key Laboratory for the Physics and Chemistry of Nanodevices | And 6 more authors.
Nano Letters | Year: 2010

A small band-gap carbon nanotube (SBG CNT) with a large diameter of 4 nm has been used to fabricate ambipolar field-effect transistors (FETs) with ultrahigh carrier mobility of more than 18 300 and 8300 cm2/V•s for holes and electrons, respectively. Using a top-gate device geometry with 12 nm HfO2 being the gate oxide, the SBG CNT-based FET exhibits an almost perfect symmetric ambipolar transfer characteristic without any noticeable hysteresis, and a highly efficient frequency doubler is constructed based on this near perfect ambipolar FET. The SBG CNT-based frequency doubler is shown to be able to operate in a large signal mode where the input AC signal, being applied to the top-gate electrode, drives the FET operating alternatively in a p- or n-region yielding an output signal at the drain electrode with doubled frequency and high conversion efficiency. For an input AC signal of 1 kHz, detailed frequency power spectrum analysis shows that more than 95% of the output signal is concentrated at the doubled frequency at 2 kHz, with a gain of more than 0.15, and this represents the highest gain so far achieved in carbon-based devices, including graphene-based devices. © 2010 American Chemical Society.


Liang S.,Key Laboratory for the Physics and Chemistry of Nanodevices | Ma Z.,Key Laboratory for the Physics and Chemistry of Nanodevices | Wu G.,Key Laboratory for the Physics and Chemistry of Nanodevices | Wei N.,Key Laboratory for the Physics and Chemistry of Nanodevices | And 6 more authors.
ACS Nano | Year: 2016

Carbon nanotubes (CNTs) are considered to be highly promising nanomaterials for multiwavelength, room-temperature infrared detection applications. Here, we demonstrate a single-tube diode photodetector monolithically integrated with a Fabry-Pérot microcavity. A ∼6-fold enhanced optical absorption can be achieved, because of the confined effect of the designed optical mode. Furthermore, taking advantage of Van-Hove-singularity band structures in CNTs, we open the possibility of developing chirality-specific (n,m) CNT-film-based signal detectors. Utilizing a concept of the "resonance and off-resonance" cavity, we achieved cavity-integrated chirality-sorted CNT-film detectors working at zero bias and resonance-allowed mode, for specific target signal detection. The detectors exhibited a higher suppression ratio until a power density of 0.07 W cm-2 and photocurrent of 5 pA, and the spectral full width at half-maximum is ∼33 nm at a signal wavelength of 1200 nm. Further, with multiple array detectors aiming at different target signals integrated on a chip, a multiwavelength signal detector system can be expected to have applications in the fields of monitoring, biosensing, color imaging, signal capture, and on-chip or space information transfers. The approach can also bring other nanomaterials into on-chip or information optoelectronics, regardless of the available doping polarity. © 2016 American Chemical Society.


Ji Q.,CAS Beijing National Laboratory for Molecular | Zhang Y.,CAS Beijing National Laboratory for Molecular | Guo Y.,Key Laboratory for the Physics and Chemistry of Nanodevices | Ma D.,CAS Beijing National Laboratory for Molecular | And 4 more authors.
Nano Letters | Year: 2015

Monolayer MoS2 prepared by chemical vapor deposition (CVD) has a highly polycrystalline nature largely because of the coalescence of misoriented domains, which severely hinders its future applications. Identifying and even controlling the orientations of individual domains and understanding their merging behavior therefore hold fundamental significance. In this work, by using single-crystalline sapphire (0001) substrates, we designed the CVD growth of monolayer MoS2 triangles and their polycrystalline aggregates for such purposes. The obtained triangular MoS2 domains on sapphire were found to distributively align in two directions, which, as supported by density functional theory calculations, should be attributed to the relatively small fluctuations of the interface binding energy around the two primary orientations. Using dark-field transmission electron microscopy, we further imaged the grain boundaries of the aggregating domains and determined their prevalent armchair crystallographic orientations with respect to the adjacent MoS2 lattice. The coalescence of individual triangular flakes governed by unique kinetic processes is proposed for the polycrystal formation. These findings are expected to shed light on the controlled MoS2 growth toward predefined domain orientation and large domain size, thus enabling its versatile applications in next-generation nanoelectronics and optoelectronics. © 2014 American Chemical Society.


PubMed | TU Ilmenau and Peking University
Type: | Journal: Chemphyschem : a European journal of chemical physics and physical chemistry | Year: 2016

This Minireview focuses exclusively on work with scanning tunneling microscopy to study the self-assembled multilayer films (SAMTs) of organic molecules. The -conjugated organic molecules form different structures within different monolayers on various substrates. The interplay between molecule-substrate and intermolecular interactions plays a key role in determining the stacking mode of organic multilayer films. Different substrates strongly influence the organic-film growth and electronic properties of the organic molecules. Geometric and electronic structures of SAMTs are important factors that may determine device performance. In addition to the inorganic interface, this Minireview addresses the organic-organic interface. Homo- and hetero-SAMTs of organic molecules are also considered. The subtle interplay between structural and electronic characteristics, on one hand, and functionality and reactivity, on the other hand, are highlighted.

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