A method to grow a relaxed Si0.5Ge0.5 graded layer with a very smooth surface and a very low threading dislocation density using solid-source molecular-beam epitaxy is reported. This method included the use of Sb as a surfactant for the growth of a 2 mm compositionally graded SiGe buffer with the Ge concentration linearly graded from 0% to 50% followed by a 0.3 mm constant Si0.5Ge0.5 layer. The...

Functional materials with compositional gradients exhibit unique characteristics that are different from the components comprising the structure. Graded ferroelectrics are very good examples to such materials where a systematic variation in composition is introduced along the thickness of a thin film heterostructure. Such structures display interesting properties including the disappearance of ...

In this work, the influence of different pulse widths (25, 50 and 100 μs) during high power impulse magnetron sputtering (HiPIMS) copper, silver zirconium was investigated in terms plasma properties combinatorial composition gradient CuAgZr film libraries. situ diagnostics via optical emission spectroscopy (OES), time-of-flight mass spectrometry (TOFMS), modified quartz crystal microbalance (m-...

Novel, unitized structures with porous Ti6Al4V alloy on one side and compositionally graded, hard CoCrMo alloy surface on the other side have been fabricated using laser engineered net shaping (LENS™) process. Gradient structures with 50%, 70% and 86% CoCrMo alloy on the top surface showed high hardness in the range of 615 and 957 HV. The gradient structures were evaluated for their in vitro we...

A universal method is reported to form graded bulk heterojunction (BHJ) organic photovoltaic devices (OPVs) by a simple solvent-fluxing process. Donors are enriched at the anode and acceptors are enriched at cathode side, matching the gradient electron and hole current across the film. Efficiency enhancements by 15-50% are achieved for all BHJ systems tested compared with the optimized regular ...

PEEK is a high strength engineering thermoplastic that suffers from a high friction coefficient and a friction induced wear mode. Past studies with 0 m PEEK and PTFE powders resulted in composite solid lubricant that (at the optimal composition) had a wear rate of k= 2× 10−9 mm3/Nm ith a friction coefficient of μ= 0.12. A compositional grading of PEEK and PTFE is implemented in this study to cr...