Pyroelectric electron emission from −Z face polar surface of lithium niobate monodomain single crystal

Bourim, El Mostafa; Moon, Chiung; Lee, Seung-Woon; Sidorkin, Vadim; Yoo, In-Kyeong

doi:10.1007/s10832-006-0387-y

Cited by 7 publications

(8 citation statements)

References 16 publications

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“…It is well known that at the equilibrium, all Ps in the crystal are fully screened by the external screening charge and no electric field exists [41]. The change of the polarization, occurring with the temperature variation, perturbs such equilibrium, causing a lack or excess of surface screening charges [42]. Consequently, an electrostatic state appears and generates a high electric field at the crystal surface.…”

Section: Fabrication Processmentioning

confidence: 99%

Twofold Self-Assembling of Nanocrystals Into Nanocomposite Polymer

Coppola

Nasti

Mandracchia

et al. 2016

IEEE J. Select. Topics Quantum Electron.

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In this paper, we introduce a single-step selfassembling process aimed at forming two-dimensional (2-D) array microstructures made from a nanocomposite polymer layer in which are dispersed CdSe-CdS nanocrystals. The novelty of the process reported here is that it operates simultaneously as a twofold process where the liquid polymer matrix is self-shaped by electrohydrodynamic pressure as a 2-D array of microstructures, while at the same time, the nanocrystals are self-assembled by dielectrophoretic forces. The proposed approach could inspire future smart fabrication techniques for producing self-assembled lensed nanocomposite layers. In principle, the method is scalable down to diameter lens up to few micrometers.

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Section: Fabrication Processmentioning

confidence: 99%

Twofold Self-Assembling of Nanocrystals Into Nanocomposite Polymer

Coppola

Nasti

Mandracchia

et al. 2016

IEEE J. Select. Topics Quantum Electron.

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“…We adopted z-cut LN crystal wafers, both sides polished and 500 mm thick. The driving crystals were micro-engineered by conventional electric eld poling 21,22 with different geometries and periods. LN crystals were subject to standard electric eld poling [21][22][23] in order to fabricate a PPLN sample.…”

Section: Experimental Configurationmentioning

confidence: 99%

Hybrid ferroelectric–polymer microfluidic device for dielectrophoretic self-assembling of nanoparticles

et al. 2014

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Carbon nanoparticles are becoming ubiquitous in many fields of science and technology. However, a grand challenge remains in assembling, patterning, and positioning or even simple manipulation of CNTs for complex functional assemblies. CNTs have in fact enormous perspectives for application in biotechnologies as bactericide agents or as prominent tools for investigating cell mechanisms, or more in general as functionalized nanoparticle-vectors, but their exploitation requires viable technology at the lab-on-a-chip scale. Many approaches have been attempted in developing technologies for manipulating CNTs. One elective approach is based on electric fields driven mechanisms such as DEP forces. A variety of chips have been designed and realized with this aim. Here we report on a novel hybrid microfluidic chip made by assembling a polar-dielectric crystal with polymeric microfluidic channels. One challenging feature of such a hybrid device approach, based on an electrode-free dielectrophoretic (DEP) approach, is that it makes use of surface charge templates for self-assembling and manipulation of CNTs in liquid media directly into a microfluidic channel. Here various examples of self-assembly in microfluidic channels as well as separation and collection of two classes of nano/ microparticles are reported. The method can open the way to novel fabrication protocols for the realisation of future flexible devices with new and more complex functionalities, highly desirable in electronics as well as in biotechnology at the lab-on-a-chip scale.

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“…Both sides polished and 500μm thick LN crystals were periodically poled by standard electric field poling [31,32] in order to achieve a square array of hexagonal reversed domains. A standard mask lithography process was used to generate the desired resist pattern and the subsequent application of high voltage pulses led to the formation of the reversed domain grating [28].…”

Section: Array Of Liquid Spherical Micro-lens Arraymentioning

confidence: 99%

“…In fact, the electrodes were built into the crystal through a micro-engineering process and were activated pyroelectrically by an appropriate temperature variation. A periodically poled polar dielectric crystal (lithium niobate) [29,30] was used as substrate and the formation of sessile micro-droplets was driven by the patterned surface charges induced by the pyroelectric effect [31]. The fundamental physics responsible of the phenomenon leading to the formation of micro-droplets was illustrated and investigated in Ref.…”

Section: Introductionmentioning

confidence: 99%

Tuneable liquid microlenses onto a functionalized polar dielectric substrates: formation and characterization

et al. 2010

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Liquid lenses are becoming important optical devices for a wide range of applications, from mobile-phone cameras to biological imaging modalities. Their biggest advantage is their potential to have a variable focus that can be changed to obtain a different radius of curvature and thus optical power. The tunability of such micro-lenses could be of great interest to the field of micro-optics thanks to the possibility to achieve focus tuning without moving parts and thus favouring the miniaturization of the optical systems. A special class of tunable liquid micro-lenses is presented here. They are generated by electro-wetting effect under an electrode-less configuration. The lensing effect is induced by the pyroelectric effect on polar dielectric crystals we named pyroelectric-electrodeless-electro-wetting (PEEW). If a thin liquid film is spin coated on a z-cut lithium niobate wafer, the pyroelectric effect causes surface-charges at the liquidsolid interface when the substrate suffers temperature changes. Electric charges build up on the substrate's surface by pyroelectricity and are responsible for the variation of the liquid contact angle, thus forming liquid micro-lenses. The temperature variation can generate a pattern of electric charges onto the surface of the crystal when ferroelectric domain pattern is micro-engineered. Different types of lenses: spherical, cylindrical and toroidal have been formed. Any temperature change allows the liquid layer to become a tunable micro-lens array, showing a strong focusing effect. A digital holography technique is used to characterize the transmitted wavefront during focusing and focal length variation in the millimetre range is observed. Formation process is illustrated while interferometric characterization and imaging properties are analyzed and discussed.

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Pyroelectric electron emission from −Z face polar surface of lithium niobate monodomain single crystal

Cited by 7 publications

References 16 publications

Twofold Self-Assembling of Nanocrystals Into Nanocomposite Polymer

Twofold Self-Assembling of Nanocrystals Into Nanocomposite Polymer

Hybrid ferroelectric–polymer microfluidic device for dielectrophoretic self-assembling of nanoparticles

Tuneable liquid microlenses onto a functionalized polar dielectric substrates: formation and characterization

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