Monte Carlo simulations reveal considerable straggling of energy loss by the same ions with the same energy in fully-depleted silicon-on-insulator （FDSOI） devices with ultra-thin sensitive silicon layers down to 2.5...Monte Carlo simulations reveal considerable straggling of energy loss by the same ions with the same energy in fully-depleted silicon-on-insulator （FDSOI） devices with ultra-thin sensitive silicon layers down to 2.5 rim. The absolute straggling of deposited energy decreases with decreasing thickness of the active silicon layer. While the relative straggling increases gradually with decreasing thickness of silicon films and exhibits a sharp rise as the thickness of the silicon film descends below a threshold value of 50 nm, with the dispersion of deposited energy ascending above ~10%. Ion species and energy dependence of the energy-loss straggling are also investigated. For a given beam, the dispersion of deposited energy results in large uncertainty on the actual linear energy transfer （LET） of incident ions, and thus single event effect （SEE） responses, which pose great challenges for traditional error rate prediction methods.展开更多
We theoretically investigate the optical properties of an ultra-thin InN layer embedded in InGaN matrix for light emitters. The peak emission wavelength extends from ultraviolet （374 nm） to green （536 nm） with InN...We theoretically investigate the optical properties of an ultra-thin InN layer embedded in InGaN matrix for light emitters. The peak emission wavelength extends from ultraviolet （374 nm） to green （536 nm） with InN quantum well thickness increasing from 1 monolayer to 2 monolayers, while the overlap of electron–hole wave function remains at a high level （larger than 90%）. Increase of In content in InGaN matrix provides a better approach to longer wavelength emission, which only reduces the spontaneous emission rate slightly compared with the case of increasing In content of the conventional InGaN quantum well. Also, the transparency carrier density derived from gain spectrum is of the same order as that in the conventional blue laser diode. Our study provides skillful design on the development of novel structure InN-based light emitting diodes as well as laser diodes.展开更多
The properties of top-contact organic thin-film transistors （TC-OTFTs） using ultra-thin 2, 9-dimethyl-4, 7- diphenyl-1, 10-phenanthroline （BCP） as a hole-blocking interlayer have been improved significantly and a ...The properties of top-contact organic thin-film transistors （TC-OTFTs） using ultra-thin 2, 9-dimethyl-4, 7- diphenyl-1, 10-phenanthroline （BCP） as a hole-blocking interlayer have been improved significantly and a BCP interlayer was inserted into the middle of the pentacene active layer. This paper obtains a fire-new transport mode of an OTFT device with double-conductible channels. The accumulation and transfer of the hole carriers arc limited by the BCP interlayer in the vertical region of the channel. A huge amount of carriers is located not only at the interface between pentacene and the gate insulator, but also at the two interfaces of pentacene/BCP interlayer and pentacene/gate insulator, respectively. The results suggest that the BCP interlayer may be useful to adjust the hole accumulation and transfer, and can increase the hole mobility and output current of OTFTs. The TC-OTFTs with a BCP interlayer at VDS = --20 V showed excellent hole mobility μFE and threshold voltage VTH of 0.58 cm^2/（V-s） and -4.6 V, respectively.展开更多
As part of a research intending to develop steel-concrete hybrid girder using ultra high performance concrete with compressive strength of 80 MPa, this study conducts loading test on this girder to investigate the met...As part of a research intending to develop steel-concrete hybrid girder using ultra high performance concrete with compressive strength of 80 MPa, this study conducts loading test on this girder to investigate the methods for its composition with a slab using 30 MPa-concrete and the corresponding interfacial behavior. Prior to the loading test, the design formula of the Eurocode for the shear resistance developed in concrete-to-concrete interface is examined for the interface between concrete layers of different strengths. The effect of the surface roughness on the shear resistance is examined using this formula and finite element analysis to verify the applicability of the formula. Based upon the results, loading test is conducted on girder specimens to evaluate the actual behavior with respect to the interfacial surface condition. The test results reveal that the specimen with rough interface could not develop perfectly composite behavior and experienced adhesive failure. In case of simultaneous action of flexure and shear, it appears that conservative design should be applied without consideration of the interfacial condition when determining the arrangement of shear reinforcement.展开更多
Using Monte Carlo simulations, we have investigated the classical XY model on triangular lattices of ultra-thin film structures with middle ferromagnetic layers sandwiched between two antiferromagnetic layers. The int...Using Monte Carlo simulations, we have investigated the classical XY model on triangular lattices of ultra-thin film structures with middle ferromagnetic layers sandwiched between two antiferromagnetic layers. The internal energy, the specifc heat, the chirality and the chiral susceptibility are calculated in order to clarify phase transitions and critical phenomena. Prom the finite-size scaling analyses, the values of critical exponents are determined. In a range of interaction parameters, we find that the chirality steeply goes up as temperature increases in a temperature range; correspondingly the value of a critical exponent for this change is estimated.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 11179003 and 10975164)
文摘Monte Carlo simulations reveal considerable straggling of energy loss by the same ions with the same energy in fully-depleted silicon-on-insulator （FDSOI） devices with ultra-thin sensitive silicon layers down to 2.5 rim. The absolute straggling of deposited energy decreases with decreasing thickness of the active silicon layer. While the relative straggling increases gradually with decreasing thickness of silicon films and exhibits a sharp rise as the thickness of the silicon film descends below a threshold value of 50 nm, with the dispersion of deposited energy ascending above ~10%. Ion species and energy dependence of the energy-loss straggling are also investigated. For a given beam, the dispersion of deposited energy results in large uncertainty on the actual linear energy transfer （LET） of incident ions, and thus single event effect （SEE） responses, which pose great challenges for traditional error rate prediction methods.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61076013, 51272008, and 51102003)the National Basic Research Program of China (Grant No. 2012CB619304)+1 种基金the Beijing Municipal Science & Technology Commission (Grant No. D111100001711002)the Specialized Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20100001120014)
文摘We theoretically investigate the optical properties of an ultra-thin InN layer embedded in InGaN matrix for light emitters. The peak emission wavelength extends from ultraviolet （374 nm） to green （536 nm） with InN quantum well thickness increasing from 1 monolayer to 2 monolayers, while the overlap of electron–hole wave function remains at a high level （larger than 90%）. Increase of In content in InGaN matrix provides a better approach to longer wavelength emission, which only reduces the spontaneous emission rate slightly compared with the case of increasing In content of the conventional InGaN quantum well. Also, the transparency carrier density derived from gain spectrum is of the same order as that in the conventional blue laser diode. Our study provides skillful design on the development of novel structure InN-based light emitting diodes as well as laser diodes.
基金supported by the National High Technology Research and Development Program of China (Grant No 2006AA03Z0412)the National Natural Science Foundation of China (Grant Nos 10774013 and 10804006)+4 种基金the Excellent Doctor’s Science and Technology Innovation Foundation of Beijing Jiaotong University (Grant No 48024)the Foundation of Beijing Jiaotong University (Grant No 2005SM057)the Research Fund for the Youth Scholars of the Doctoral Program of Higher Education (Grant No 20070004031)the Beijing NOVA program (Grant No 2007A024)Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘The properties of top-contact organic thin-film transistors （TC-OTFTs） using ultra-thin 2, 9-dimethyl-4, 7- diphenyl-1, 10-phenanthroline （BCP） as a hole-blocking interlayer have been improved significantly and a BCP interlayer was inserted into the middle of the pentacene active layer. This paper obtains a fire-new transport mode of an OTFT device with double-conductible channels. The accumulation and transfer of the hole carriers arc limited by the BCP interlayer in the vertical region of the channel. A huge amount of carriers is located not only at the interface between pentacene and the gate insulator, but also at the two interfaces of pentacene/BCP interlayer and pentacene/gate insulator, respectively. The results suggest that the BCP interlayer may be useful to adjust the hole accumulation and transfer, and can increase the hole mobility and output current of OTFTs. The TC-OTFTs with a BCP interlayer at VDS = --20 V showed excellent hole mobility μFE and threshold voltage VTH of 0.58 cm^2/（V-s） and -4.6 V, respectively.
文摘As part of a research intending to develop steel-concrete hybrid girder using ultra high performance concrete with compressive strength of 80 MPa, this study conducts loading test on this girder to investigate the methods for its composition with a slab using 30 MPa-concrete and the corresponding interfacial behavior. Prior to the loading test, the design formula of the Eurocode for the shear resistance developed in concrete-to-concrete interface is examined for the interface between concrete layers of different strengths. The effect of the surface roughness on the shear resistance is examined using this formula and finite element analysis to verify the applicability of the formula. Based upon the results, loading test is conducted on girder specimens to evaluate the actual behavior with respect to the interfacial surface condition. The test results reveal that the specimen with rough interface could not develop perfectly composite behavior and experienced adhesive failure. In case of simultaneous action of flexure and shear, it appears that conservative design should be applied without consideration of the interfacial condition when determining the arrangement of shear reinforcement.
基金Project supported by the National Natural Science Foundation of China （Grant No 10234010）, Acknowledgements The authors would like to thank Professor T. Horiguch for his useful discussion. 0ur simulations were carried out on IBM RS/6000 SP3 at the Centre for Computational Science and Engineering of Peking University.
文摘Using Monte Carlo simulations, we have investigated the classical XY model on triangular lattices of ultra-thin film structures with middle ferromagnetic layers sandwiched between two antiferromagnetic layers. The internal energy, the specifc heat, the chirality and the chiral susceptibility are calculated in order to clarify phase transitions and critical phenomena. Prom the finite-size scaling analyses, the values of critical exponents are determined. In a range of interaction parameters, we find that the chirality steeply goes up as temperature increases in a temperature range; correspondingly the value of a critical exponent for this change is estimated.
