| 1. |
- Liu, Tao, et al.
(författare)
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16% efficiency all-polymer organic solar cells enabled by a finely tuned morphology via the design of ternary blend
- 2021
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Ingår i: Joule. - : CELL PRESS. - 2542-4351. ; 5:4, s. 914-930
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Tidskriftsartikel (refereegranskat)abstract
- A SUMMARY There is an urgent demand for all-polymer organic solar cells (AP-OSCs) to gain higher efficiency. Here, we successfully improve the performance to 16.09% by introducing a small amount of BN-T, a B <- N-type polymer acceptor, into the PM6:PY-IT blend. It has been found that BN-T makes the active layer, based on the PM6:PY-IT:BN-T ternary blend, more crystalline but meanwhile slightly reduces the phase separation, leading to enhancement of both exciton harvesting and charge transport. From a thermodynamic viewpoint, BN-T prefers to reside between PM6 and PY-IT, and the fraction of this fine-tunes the morphology. Besides, a significantly reduced nonradiative energy loss occurs in the ternary blend, along with the coexistence of energy and charge transfer between the two acceptors. The progressive performance facilitated by these improved properties demonstrates that AP-OSCs can possibly comparably efficient with those based on small molecule acceptors, further enhancing the competitiveness of this device type.
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| 2. |
- Li, Junjie, et al.
(författare)
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A Novel Dry Selective Isotropic Atomic Layer Etching of SiGe for Manufacturing Vertical Nanowire Array with Diameter Less than 20 nm
- 2020
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:3
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Tidskriftsartikel (refereegranskat)abstract
- Semiconductor nanowires have great application prospects in field effect transistors and sensors. In this study, the process and challenges of manufacturing vertical SiGe/Si nanowire array by using the conventional lithography and novel dry atomic layer etching technology. The final results demonstrate that vertical nanowires with a diameter less than 20 nm can be obtained. The diameter of nanowires is adjustable with an accuracy error less than 0.3 nm. This technology provides a new way for advanced 3D transistors and sensors.
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| 3. |
- Fan, Qunping, 1989, et al.
(författare)
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Mechanically Robust All-Polymer Solar Cells from Narrow Band Gap Acceptors with Hetero-Bridging Atoms
- 2020
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Ingår i: Joule. - : Elsevier BV. - 2542-4351. ; 4:3, s. 658-672
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Tidskriftsartikel (refereegranskat)abstract
- We developed three narrow band-gap polymer acceptors PF2-DTC, PF2-DTSi, and PF2-DTGe with different bridging atoms (i.e., C, Si, and Ge). Studies found that such different bridging atoms significantly affect the crystallinity, extinction coefficient, electron mobility of the polymer acceptors, and the morphology and mechanical robustness of related active layers. In all-polymer solar cells (all-PSCs), these polymer acceptors achieved high power conversion efficiencies (PCEs) over 8.0%, while PF2-DTSi obtained the highest PCE of 10.77% due to its improved exciton dissociation, charge transport, and optimized morphology. Moreover, the PF2-DTSi-based active layer showed excellent mechanical robustness with a high toughness value of 9.3 MJ m−3 and a large elongation at a break of 8.6%, which is a great advantage for the practical applications of flexible devices. As a result, the PF2-DTSi-based flexible all-PSC retained >90% of its initial PCE (6.37%) after bending and relaxing 1,200 times at a bending radius of ∼4 mm.
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| 4. |
- Zhang, Ying, et al.
(författare)
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On Modeling and Detecting Trojans in Instruction Sets
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Ingår i: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems. - 0278-0070. ; , s. 1-1
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Tidskriftsartikel (refereegranskat)abstract
- Amid growing concerns about hardware security, comprehensive security testing has become essential for chip certification. This paper proposes a deep-testing method for identifying Trojans of particular concern to middle-to-high-end users, with a focus on illegal instructions. A hidden instruction Trojan can employ a low-probability sequence of normal instructions as a boot sequence, which is followed by an illegal instruction that triggers the Trojan. This enables the Trojan to remain deeply hidden within the processor. It then exploits an intrusion mechanism to acquire Linux control authority by setting a hidden interrupt as its payload. We have developed an unbounded model checking (UMC) technique to uncover such Trojans. The proposed UMC technique has been optimized with slicing based on the input cone, head-point replacement, and backward implication. Our experimental results demonstrate that the presented instruction Trojans can survive detection by existing methods, thus allowing normal users to steal root user privileges and compromising the security of processors. Moreover, our proposed deep-testing method is empirically shown to be a powerful and effective approach for detecting these instruction Trojans.
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| 5. |
- Chen, Hong, et al.
(författare)
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PKU-3 : An HCI-Inclusive Aluminoborate for Strecker Reaction Solved by Combining RED and PXRD
- 2015
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 137:22, s. 7047-7050
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Tidskriftsartikel (refereegranskat)abstract
- A novel microporous aluminoborate, denoted as PKU-3, was prepared by the boric acid flux method. The structure of PKU-3 was determined by combining the rotation electron diffraction and synchrotron powder X-ray diffraction data with well resolved ordered Cl- ions in the channel. Composition and crystal structure analysis showed that there are both proton and chlorine ions in the channels. Part of these protons and chlorine ions can be washed away by basic solutions to activate the open pores. The washed PKU-3 can be used as an efficient catalyst in the Strecker reaction with yields higher than 90%.
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| 6. |
- Cong, Rihong, et al.
(författare)
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Syntheses and Crystal Structures of Two New Bismuth Hydroxyl Borates Containing [Bi(2)O(2)](2+) Layers : Bi(2)O(2)[B(3)O(5)(OH)] and Bi(2)O(2)[BO(2)(OH)]
- 2011
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 50:11, s. 5098-5104
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Tidskriftsartikel (refereegranskat)abstract
- Two new bismuth hydroxyl borates, Bi(2)O(2)[B(3)O5-(OH)] (I) and Bi(2)O(2)[BO(2)(OH)] (II), have been synthesized under hydrothermal conditions. Their structures were determined by single-crystal and powder X-ray diffraction data, respectively. Compound I crystallizes in the orthorhombic space group Pbca with the lattice constants of a = 6.0268(3) angstrom, b = 11.3635(6) angstrom, and c = 19.348(1) angstrom. Compound II crystallizes in the monoclinic space group Cm with the lattice constants of a = 5.4676(6) angstrom, b = 14.6643(5) angstrom, c = 3.9058(1) angstrom, and beta = 135.587(6)degrees. The borate fundamental building block (FBB) in I is a three-ring unit [B(3)O(6)(OH)](4-), which connects one by one via sharing corners, forming an infinite zigzag chain along the a direction. The borate chains are further linked by hydrogen bonds, showing as a borate layer within the ab plane. The FBB in II is an isolated [BO(2)(OH)](2-) triangle, which links to two neighboring FBBs by strong hydrogen bonds, resulting in a borate chain along the a direction. Both compounds contain [Bi(2)O(2)](2+) layers, and the [Bi(2)O(2)](2+) layers combine with the corresponding borate layers alternatively, forming the whole structures. These two new bismuth borates are the first ones containing [Bi(2)O(2)](2+) layers in borates. The appearance of Bi(2)O(2)[BO(2)(OH)] (II) completes the series of compounds Bi(2)O(2)[BO(2)(OH)], Bi(2)O(2)CO(3), and Bi(2)O(2)[NO(3)(OH)] and the formation of Bi(2)O(2)[B(3)O(5)(OH)] provides another example in demonstrating the polymerization tendency of borate groups.
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| 7. |
- Li, Kezhi, et al.
(författare)
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Piecewise sparse signal recovery via piecewise orthogonal matching pursuit
- 2016
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Ingår i: 2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479999880 ; , s. 4608-4612
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Konferensbidrag (refereegranskat)abstract
- In this paper, we consider the recovery of piecewise sparse signals from incomplete noisy measurements via a greedy algorithm. Here piecewise sparse means that the signal can be approximated in certain domain with known number of nonzero entries in each piece/segment. This paper makes a two-fold contribution to this problem: 1) formulating a piecewise sparse model in the framework of compressed sensing and providing the theoretical analysis of corresponding sensing matrices; 2) developing a greedy algorithm called piecewise orthogonal matching pursuit (POMP) for the recovery of piecewise sparse signals. Experimental simulations verify the effectiveness of the proposed algorithms.
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| 8. |
- Wang, Guilei, et al.
(författare)
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Growth of SiGe layers in source and drain regions for 10 nm node complementary metal-oxide semiconductor (CMOS)
- 2020
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Ingår i: Journal of materials science. Materials in electronics. - : Springer Science and Business Media LLC. - 0957-4522 .- 1573-482X. ; 31, s. 26-33
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the integration of Si 1−x Ge x (50% ≤ x ≤ 60%) selective epitaxy on source/drain regions in 10 nm node FinFET has been presented. One of the major process issues was the sensitivity of Si-fins’ shape to ex- and in-situ cleaning prior to epitaxy. For example, the sharpness of Si-fins could easily be damaged during the wafer washing. The results showed that a DHF dip before the normal cleaning, was essential to clean the Si-fins while in-situ annealing in range of 780–800 °C was needed to remove the native oxide for high epitaxial quality. Because of smallness of fins, the induced strain by SiGe could not be directly measured by X-ray beam in a typical XRD tool in the lab or even in a Synchrotron facility. Further analysis using nano-beam diffraction technique in high-resolution transmission electron microscope also failed to provide information about strain in the FinFET structure. Therefore, the induced strain by SiGe was simulated by technology computer-aided design program and the Ge content was measured by using energy dispersive spectroscopy. Simulation results showed 0.8, 1 and 1.3 GPa for Ge content of 40%, 50% and 60%, respectively. A kinetic gas model was also introduced to predict the SiGe profile on Si-fins with sharp triangular shape. The input parameters in the model includes growth temperature, partial pressure of the reactant gases and the exposed Si coverage in the chip area.
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| 9. |
- Wang, Guilei, et al.
(författare)
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pMOSFETs Featuring ALD W Filling Metal Using SiH4 and B2H6 Precursors in 22 nm Node CMOS Technology
- 2017
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Ingår i: Nanoscale Research Letters. - : SPRINGER. - 1931-7573 .- 1556-276X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, pMOSFETs featuring atomic layer deposition (ALD) tungsten (W) using SiH4 and B2H6 precursors in 22 nm node CMOS technology were investigated. It is found that, in terms of threshold voltage, driving capability, carrier mobility, and the control of short-channel effects, the performance of devices featuring ALD W using SiH4 is superior to that of devices featuring ALD W using B2H6. This disparity in device performance results from different metal gate-induced strain from ALD W using SiH4 and B2H6 precursors, i.e. tensile stresses for SiH4 (similar to 2.4 GPa) and for B2H6 (similar to 0.9 GPa).
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| 10. |
- Wang, Guilei, et al.
(författare)
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Study of SiGe selective epitaxial process integration with high-k and metal gate for 16/14 nm nodes FinFET technology
- 2016
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Ingår i: Microelectronic Engineering. - : Elsevier. - 0167-9317 .- 1873-5568. ; 163, s. 49-54
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the process integration of SiGe selective epitaxy on source/drain regions, for 16/14 nm nodes FinFET with high-k & metal gate has been presented. Selectively grown Si1-xGex (0.35 <= x <= 0.40) with boron concentration of 1 x 10(20) cm(-3) was used to elevate the source/drain of the transistors. The epi-quality, layer profile and strain amount of the selectively grown SiGe layers were also investigated by means of various characterizations. A series of prebaking experiments were performed for temperatures ranging from 740 to 825 degrees C in order to in situ clean the Si fins prior to the epitaxy. The results showed that the thermal budget needs to be limited to 780-800 degrees C in order to avoid any damages to the shape of Si fins but to remove the native oxide effectively which is essential for high epitaxial quality. The Ge content in SiGe layers on Si fins was determined from the strain measured directly by reciprocal space mappings using synchrotron radiation. Atomic layer deposition technique was applied to fill the gate trench with W using WF6 and B2H6 precursors. By such an AID approach, decent growth rate, low resistivity and excellent gap filling capability of W in pretty high aspect-ratio gate trench was realized. The as-fabricated FinFETs demonstrated decent electrical characteristics.
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