Journal of Advanced Dielectrics

This editorial celebrates the 10^th anniversary of Journal of Advanced Dielectrics (JAD) which was launched in January 2011.

Doped lead–zirconate–titanate (PZT) thin films are preferred for the development of micro–electro–mechanical systems (MEMS)-based acoustic sensors because of their inherent higher dielectric and piezoelectric coefficients. Patterning process is used to develop such MEMS devices which is highly complex even for undoped PZT thin films; therefore, the problem is further cumbersome for doped PZT thin films due to the presence of added dopant elements and their associated chemistry. This paper presents patterning of strontium (Sr) and lanthanum (La) co-doped PZT thin film (PSLZT) deposited on platinized silicon substrate using wet and dry etching processes for fabricating a diaphragm structure with thickness of 15–25$\mu$m and diameter of 1.4–2mm, suitable for acoustic sensing applications. The effects of various etching conditions have been studied and the results are reported. It is found that the dry etching is the most suited process for realizing the piezoelectric MEMS structure due to its higher etching resolution. An appreciable etching rate of 260–270nm/min with smooth vertical sidewalls is achieved. The silicon diaphragm with patterned PSLZT thin film is found to retain more than 80% of its dielectric and piezoelectric coefficients and has a resonance of 1.43MHz.

Sintered lead-free ${\text{Bi}}_{0.5}$(${\text{Na}}_{0.8}$${\text{K}}_{0.2}{)}_{0.5}$(${\text{Ti}}_{0.96}$${\text{Sn}}_{0.04})$O₃ ceramics (BNKTS) have been fabricated via a solid-state reaction. The effect of sintering temperature on the structural, morphological, dielectric, ferroelectric and energy storage properties of BNKTS ceramics was investigated, and it was found that the electrical properties of the synthesized ceramics increased with the increase in the sintering temperature, and the highest values were achieved at $1100^{\circ }$C. The ceramics sintered at the optimized temperature of $1100^{\circ }$C exhibited the best physical, dielectric, ferroelectric and energy storage properties, namely, high density (the relative density, $\rho =5.88$g.cm${}^{-3}$, approximate to 96.7% of the theoretical value), high densification factor ($\mathrm{\text{DF}}=0.93$), high dielectric constant (${\epsilon }_r=1215$), low dielectric loss (tan$\delta =0.051$), highest dielectric constant (${\epsilon }_{max}=4335$), high remanent polarization ($P_r=9.5\mu$C.cm${}^{-2})$, high coercive field ($E_c=14.3$kV/cm), high energy storage density (0.12J/cm${}^3)$, and high energy storage efficiency (41.7% at 46.3kV/cm).

The results of a comprehensive study of the crystal structure, grain structure, and strength properties of ceramic bismuth ferrite with rare earth elements (REE) obtained by two-stage solid-phase synthesis followed by sintering using conventional ceramic technology are presented. The reasons for the formation of low mechanical strength and the development of destruction phenomena in solid solutions with small REE ($\bar{R}<0.94$ Å) are considered: Tb, Dy, Ho, Er, Tm, Yb, Lu. The causes of the observed phenomena associated with the composite-like structure of the studied media and, as a consequence, the occurrence of local stresses of structural elements that provoke crack formation are established. A source of the latter are also the structural features of the grain landscape. The conclusion is made about the appropriateness of taking into account the information obtained when developing devices based on BiFeO₃/REE multiferroics.

Development of novel biomaterials for bone regeneration is based on the sufficient bone-bonding ability, bioactivity and biocompatibility. In this study, novel flexible poly(butylene succinate)/polydimethysiloxane-modified bioactive glass/nano-hydroxyapatite (PBSu/PDMS-BG/nHA) hybrid bioceramic with various nHA concentration on the in vitro bone-like hydroxyapatite (HA) formation, biomineralization activity and osteoblast cell biocompatibility were investigated. The rapid precipitation of HA on the hybrid bioceramic surfaces was found after being immersed in simulated body fluid (SBF) for seven days. Results show that the amount of HA deposition increased with the increase of nHA concentration. The optimized PBSu/PDMS-BG/nHA hybrid bioceramic exhibited good flexibility, high biomineralization activity and good osteoblast cell biocompatibility.

New lead-free piezoceramic nanocomposites of Boron Sodium Gadolinium Niobate (BNGN), with general formula (1$-x)$${\text{B}}_{0.5}$${\text{Na}}_{0.5}$${\text{GdO}}_3-$$x$${\text{B}}_{0.5}$${\text{Na}}_{0.5}$NbO₃, exhibiting a Morphotropic Phase Boundary (MPB), have been synthesized following hydrothermal method followed by solid state sintering. The occurrence of MPB at the composition with $x=0.55$, at which rhombohedral and monoclinic phases are found to coexist, has been confirmed using powder XRD. This accounts for the occurrence of large remnant polarization when the sintered ceramic pellets are subjected to electric poling at 2KV/mm. Uniform microstructure of various compositions is confirmed by SEM imaging. Dielectric and piezoelectric properties of the samples are found to be comparable to those of commercial grade PZT. At the MPB, the ${\text{d}}_{33}$ coefficient is found to be 556 pC/N, which is close to that of commercial grade PZT, which makes BNGN a promising material to substitute lead containing PZT in the near future.

A system of hydrostatic parameters is studied in novel 2–0–2 composites that contain two lead-free piezoelectric single-crystal components. The ferroelectric domain-engineered alkali niobate-tantalate-based single-crystal layer promotes large values of the piezoelectric coefficients $g_{33}^{\ast }$ and $g_h^{\ast }$, hydrostatic squared figure of merit $d_h^{\ast }{g}_h^{\ast }$, and hydrostatic electromechanical coupling factor $k_h^{\ast }$ of the composite wherein the 0–3 Li₂B₄O₇ single crystal/polyethylene layers are adjacent to the aforementioned single-crystal layer. Hereby, the role of the elastic anisotropy of the 0–3 layer is emphasized. An orientation effect concerned with rotations of the crystallographic axes of the piezoelectric Li₂B₄O₇ single crystal in the 0–3 layer is first studied. It is shown that the orientation of the crystallographic axis $Z$ of the Li₂B₄O₇ single crystal in the polymer matrix strongly influences the piezoelectric properties and hydrostatic parameters of the composite. Examples of the so-called waterfall-like orientation dependences of the hydrostatic parameters are analyzed. The composite based on the domain-engineered [Li_x(${\text{K}}_{1-y}$${\text{Na}}_y{)}_{1-x}$](${\text{Nb}}_{1-z}$${\text{Ta}}_z)$O₃:Mn single crystal is of interest due to $g_h^{\ast }\sim 10^2$mV$\cdot$m/N, $d_h^{\ast }{g}_h^{\ast }\sim 10^{-10}$ Pa${}^{-1}$, and $k_h^{\ast }\approx 0.70$–0.75 in the studied volume-fraction and orientation ranges, and these hydrostatic parameters are to be taken into account in the field of piezotechnical, hydroacoustic, and energy-harvesting applications.

Antimony selenide is a promising semiconductor with great application potential in the fields of optoelectronic devices. In this work, the vapor transport deposition (VTD) method is employed to prepare Sb₂Se₃ films on substrates. The influence of deposition temperature, distance between the Sb₂Se₃ sources and substrate, and the deposition holding time on the film morphology is investigated in detail. The deposited Sb₂Se₃ thin film is employed to fabricate photodetector with a structure of ITO/SnO₂/Sb₂Se₃/Au, where the spin-coated SnO₂ film is used as the buffer layer. The device demonstrates relative high responsivity in the range of 300–1000nm with a maximum value of 312mA W${}^{-1}$ at 750nm.

In this paper, Carbon-doped Zinc Oxide (C-ZnO) samples were prepared using the solid-state reaction method. The influence of carbon-doping on the structural and dielectric properties of ZnO samples was studied. The shift in the highest peak position (101) in XRD patterns of carbon-doped samples was observed. The Raman peak at 581cm${}^{-1}$ in undoped ZnO was shifted and broadened in carbon-doped ZnO samples. The ZnO samples doped with carbon show higher values of dielectric constant ($\sim 2400$ at 1kHz) compared to pure ZnO($\sim 9$ at 1kHz) which was due to increase in native point defects in the samples. The ac conductivity (${\sigma }_{\mathrm{\text{ac}}}$) value of the carbon-doped sample was enhanced by 10³ times for ((ZnO)${}_{0.9}$ ${\text{C}}_{0.1}$) sample.