multilaags

Multilaags, or multilayers, are structures made of several adjacent layers of materials with distinct properties. The layers are usually thin (nanometers to micrometers) and stacked to create functions not present in a single material, with performance depending on thickness, interfaces, and material contrast.

Common fabrication methods include physical vapor deposition (PVD, such as sputtering and evaporation), chemical vapor deposition (CVD), atomic layer deposition (ALD), and layer-by-layer assembly in solution. Precise thickness control and smooth interfaces are essential for reliable behavior.

Optical multilayers use interference from alternating high and low refractive index materials to reflect or transmit wavelengths. Dielectric mirrors and Bragg reflectors are typical; magnetic or electronic multilayers can couple adjacent layers to tailor magnetic or electronic properties.

Applications span coatings, optics, and electronics. Coatings can provide anti-reflection, corrosion resistance, or hardness. In optics, dielectric mirrors enable lasers and sensors. In energy devices, multilayers appear in solar cells and light-emitting diodes; in data storage, magnetic multilayers underpin some read heads and spintronic devices.

Design considerations include matching thermal expansion to minimize stress, controlling interfacial roughness, and avoiding interdiffusion that degrades performance. Layer-by-layer deposition of polymers and biopolymers is another approach.

Notable examples include GaAs/AlAs superlattices, oxide/oxide multilayers, and Fe/Cr magnetic multilayers, with ongoing research into new materials and architectures that exploit layering.