Diffusion of Niobium in Congruent Lithium Niobate

Born, E.; Hornsteiner, J.; Metzger, T. H.; Riha, E.

doi:10.1002/(sici)1521-396x(200002)177:2<393::aid-pssa393>3.0.co;2-f

Cited by 3 publications

(5 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Niobium ions (Nb 5+ ) may also potentially diffuse with the help of lithium vacancies, as the ionic radii of niobium ions (r Nb 5+ = 64pm) and lithium ions (r Li + = 76pm) are similar 12,24 . For the electronic conductivity, polarons and bipolarons may be involved 23 , which would also increase with an increasing number of vacancies in the crystal.…”

Section: Fig 4 Relative Contribution Of Each Charge Carrier To the Ov...mentioning

confidence: 99%

“…Indeed, practical applications of lithium niobate have found that the experimentally observable piezoelectric behavior can degrade well be-low the Curie temperature. The literature reports practical piezoelectric limits as low as 573 K, although there is significant variability [6][7][8][9][10][11][12] . In contrast, other researchers 8,[13][14][15] have demonstrated that lithium niobate keeps its piezoelectric properties for several hours and even days in high temperature environments.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High-temperature electrical conductivity in piezoelectric lithium niobate

Lucas

Bouchy

Bélanger

et al. 2022

Journal of Applied Physics

View full text Add to dashboard Cite

Lithium niobate is a promising candidate for use in high-temperature piezoelectric devices due to its high Curie temperature ([Formula: see text]1483 K) and strong piezoelectric properties. However, the piezoelectric behavior has, in practice, been found to degrade at various temperatures as low as 573 K, with no satisfactory explanation available in the literature. We, therefore, studied the electrical conductivity of congruent lithium niobate single crystals in the temperature range of 293–1273 K with an 500 mV excitation at frequencies between 20 Hz and 20 MHz. An analytical model that generalizes the universal dielectric relaxation law with the Arrhenius equation was found to describe the experimental temperature and frequency dependence and helped discriminate between conduction mechanisms. Electronic conduction was found to dominate at low temperatures, leading to low overall electrical conductivity. However, at high temperatures, the overall electrical conductivity increases significantly due to ionic conduction, primarily with lithium ions (Li+) as charge carriers. This increase in electrical conductivity can, therefore, cause an internal short in the lithium niobate crystal, thereby reducing observable piezoelectricity. Interestingly, the temperature above which ionic conductivity dominates depends greatly on the excitation frequency: at a sufficiently high frequency, lithium niobate does not exhibit appreciable ionic conductivity at high temperature, helping explain the conflicting observations reported in the literature. These findings enable an appropriate implementation of lithium niobate to realize previously elusive high-temperature piezoelectric applications.

show abstract

Section: Fig 4 Relative Contribution Of Each Charge Carrier To the Ov...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High-temperature electrical conductivity in piezoelectric lithium niobate

Lucas

Bouchy

Bélanger

et al. 2022

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…Corresponding author: T. Aubert (thierry.aubert@centralesupelec.fr). [11][12]. The kinetics of this process becomes really problematic above 400°C [13].…”

mentioning

confidence: 99%

Stoichiometric Lithium Niobate Crystals: Towards Identifiable Wireless Surface Acoustic Wave Sensors Operable up to 600 °C

et al. 2019

View full text Add to dashboard Cite

Wireless surface acoustic wave (SAW) sensors constitute a promising solution to some unsolved industrial sensing issues taking place at high temperatures. Currently, this technology enables wireless measurements up to 600-700°C at best. However, the applicability of such sensors remains incomplete since they do not allow identification above 400°C. The latter would require the use of a piezoelectric substrate providing a large electromechanical coupling coefficient K 2 , while being stable at high temperature. In this letter, we investigate the potentiality of stoichiometric lithium niobate (sLN) crystals for such purpose. Raman spectroscopy and X-ray diffraction attest that sLN crystals withstand high temperatures up to 800°C, at least for several days. In situ measurements of sLN-based SAW resonators conducted up to 600°C show that the K 2 of these crystals remains high and stable throughout the whole experiment, which is very promising for the future achievement of identifiable wireless high-temperature SAW sensors.

show abstract

“…For example, LiNbO 3 segregation at the surface 6 can give rise to micrometer high structures rising above the wafer surface and accompanied by shallow, micrometer deep grooves. These grooves are associated with Nb diffusion that occurs only at the crystal surface and along defect planes.…”

mentioning

confidence: 99%

“…These grooves are associated with Nb diffusion that occurs only at the crystal surface and along defect planes. As a result, ''rope-like ladders'' structure, 6 extending inside the wafer, can be detected. Moreover, low-angle grain boundaries along the z axis, voids, and small decanted interfaces 7 have also been observed and linked with the crystal growth and pulling rate.…”

mentioning

confidence: 99%

Latency effects and periodic structures in light-induced frustrated etching of Fe:doped LiNbO3

Boyland

Mailis

Barry

et al. 2000

Applied Physics Letters

View full text Add to dashboard Cite

Single crystals of z-cut 0.05% Fe:doped lithium niobate (Fe:LiNbO 3 ), have been etched in a mixture of HF and HNO 3 acids, under simultaneous illumination from a ϳ100 mW 488 nm wavelength Ar ion laser light source, focused to power densities of ϳ50 W cm Ϫ2 at the crystal surface exposed to the etchant. Etching is partially inhibited in illuminated regions, and the degree of inhibition shows a systematic latency: sites illuminated early in the etch run resist further etching even after the light is removed. Etched structures additionally exhibit regular periodic features of ϳ0.5 m scale length. Details of these structures are shown, and the latent etching effect is discussed. © 2000 American Institute of Physics. ͓S0003-6951͑00͒00844-5͔Structuring of photonic and optoelectronic materials at sub-m scale lengths continues to have considerable interest in areas such as photonic crystal solids, 1 Bragg grating fabrication, 2 tips for scanning probe microscopes, and the developing area of optical MEMS. 3 In all cases, such structuring requires methodologies for, and accurate control of, the patterning, processing and subsequent revealing stages for the features to be fabricated. In this letter, we report new results in the microstructuring of iron doped lithium niobate single crystals for which the normal etch characteristics are modified through a photoelectrochemical process at the lithium niobate/etchant interface. We observe a latent effect, in which illumination of the sample has a marked effect on subsequent etching behavior for periods of at least several hours after the illumination has been removed, and show arrays of periodic features of ϳ0.5 m scale lengths that result from this latent etch behavior.Initial results in light induced frustrated etching ͑LIFE͒ in Fe:doped LiNbO 3 have already been reported. 4 These preliminary results however were directed mainly at total suppression of etching, and additionally used more heavily doped (0.2%)Fe:LiNbO 3 . Details of the LIFE process can be found in Ref. 4, but for clarity we briefly review the etch frustration procedure, whose implementation is illustrated in Fig. 1.The etch cell is constructed from stainless steel and PTFE, which has good etch resistance from the 1:2 mixture of HF and HNO 3 acids used. The LiNbO 3 crystal was a z-cut oriented, 0.5 mm thick sample of dimensions 10 mm square, doped with 0.05 wt % Fe, and supplied by Castech, China, oriented with the Ϫz face uppermost. When exposed to the etchant, the Ϫz face will etch at a rate of ϳ1 m per hour at room temperature, while the ϩz face remains almost totally unaffected. However, when moderate cw visible laser power densities ͑ϳ1 W cm Ϫ2 ͒ are directed at the LiNbO 3 interface undergoing etching this normal etch rate can be drastically modified, yielding complete etch frustration at power densities of ϳ100 W cm Ϫ2 , and partial frustration for power levels down to ϳ1 W cm Ϫ2 . The laser light used here, unlike that reported for Ref. 4, was passed through a spatial filter assembly, consisting of two...

show abstract

Diffusion of Niobium in Congruent Lithium Niobate

Cited by 3 publications

References 14 publications

High-temperature electrical conductivity in piezoelectric lithium niobate

High-temperature electrical conductivity in piezoelectric lithium niobate

Stoichiometric Lithium Niobate Crystals: Towards Identifiable Wireless Surface Acoustic Wave Sensors Operable up to 600 °C

Latency effects and periodic structures in light-induced frustrated etching of Fe:doped LiNbO3

Contact Info

Product

Resources

About