Compositionally graded barium strontium titanate @(BaxSr12x)TiO3—BST, x50.75, 0.8, 0.9, and 1.0# thin films are fabricated by pulsed-laser deposition on a LaAlO3 substrate with (La0.7Sr0.3)MnO3 as the bottom electrode. A high dielectric permittivity and temperature characteristic without Curie–Weiss law are obtained. A tunability of over 70% is obtained at frequency of 1 MHz, which is higher th...

In this work we compare the effect of the buffer layer on the device quality and surface morphology of strained InGaAs/AlGaAs PIN multiple quantum well ~MQW! modulators. We examine GaAs buffer layers and linearly graded InGaAs buffer layers. Our results indicate that for lower indium concentrations in the quantum wells ~less than about 23%! better device performance and surface morphology are o...

In this work, the problem of a curved functionally graded piezoelectric (FGP) actuator with sandwich structure under electrical and thermal loads is investigated. The middle layer in the sandwich structure is functionally graded with the piezoelectric coefficient g31 varying continuously along the radial direction of the curved actuator. Based on the theory of linear piezoelectricity, analytica...

An analytical method for predicting elastic–plastic stress distribution in a cylindrical pressure vessel has been presented. The vessel material was a ceramic/metal functionally graded material, i.e. a particle–reinforcement composite. It was assumed that the material’s plastic deformation follows an isotropic strain-hardening rule based on the von-Mises yield criterion, and that the vessel was...

The strain relaxation mechanism and defect properties of compositionally step-graded InAsyP1−y buffers grown by molecular beam epitaxy on InP have been investigated. InAsP layers having lattice misfits ranging from 1% to 1.4% with respect to InP, as well as subsequently grown lattice matched In0.69Ga0.31As overlayers on the metamorphic buffers were explored on both 100 and 2° offcut 100 InP sub...

To enhance the distribution of their seeds, plants often utilize hygroscopic deformations that actuate dispersal mechanisms. Such movements are based on desiccation-induced shrinkage of tissues in predefined directions. The basic hygroscopic deformations are typically actuated by a bi-layer configuration, in which shrinking of an active tissue layer is resisted by a stiff layer, generating a se...

In this paper a novel anti-reflection (AR) coating based on silicon nano-bars is designed and its impact on the performance of crystalline silicon (c-Si) thin-film solar cells is extensively studied. Silicon nano-bars with optimized size and period are embedded on top of the active layer, under a 100nm Si3N4 layer. As a result of the proposed layer stack, an inhomogeneous intermediate layer wit...