International. An international team of researchers, coordinated by Leibniz IPHT in Jena, Germany, manages for the first time to observe the novel growth effects of tin coatings on surfaces structured with silicon nanometers.
The chemical composition of the deposited thin films can be precisely controlled and monitored in the future, opening up new applications in the fields of biophotonics, power generation or mobility.
Nanoscale coatings with functional materials play an important role in many sensory, electronic and photonic applications. Tin-containing layers are in demand for a wide variety of electronic parts and components in the electrical industry, as well as in sensor or photovoltaic technology.
Researchers at the Leibniz Institute for Photonics Technology (Leibniz IPHT) investigated the process of developing nanoscale tin layers together with scientists from Germany, Russia and Britain.
The starting material for the observed growth processes of tin-containing thin films are ultra-thin silicon-based structures in the form of nanowires with a diameter of less than 100 nanometers.
In experimental studies, the researchers were able to demonstrate for the first time a specific distribution effect of tin along these silicon nanostructures, tin-containing layers with different degrees of oxidation were formed along the semiconductor nanowires by means of metal-organic, chemical vapor deposition at a deposition temperature of 600 degrees Celsius.
"By understanding how tin coatings grow and what factors influence this growth process, we create the conditions to specifically control coating processes," explained Dr. Vladimir Sivakov, head of the Silicon Nanostructures Group at Leibniz IPHT.
"This makes it possible to refine the surfaces very precisely and equip them with the desired functional properties in predefined positions," added Dr. Vladimir Sivakov.
Nanometric coatings with tin enable specific optical and electrical properties and allow, among other things, to further enhance the research and development of optical and biophotonic methods.
Tin layers can be used as UV-SERS active surfaces in surface-enhanced Raman dispersion spectroscopy (SERS), which can be applied to determine the molecular fingerprint of biological samples using SERS active metal nanostructures. In addition, there are areas of application in gas sensors in which tin reacts to gases as a highly sensitive layer.
Application scenarios are also conceivable in high-performance lithium-ion batteries for electromobility and thermal energy storage, in which tin-coated anodes ensure high electronic conductivity.
The researchers investigated the growth dynamics of tin-based layers observed on nanostructured surfaces using microscopic and spectroscopic methods.
Unlike flat, unstructured silicon surfaces, in which deposition was done homogeneously, the surfaces of semiconductor nanowires were covered with tin-containing crystals of different sizes and shapes along their entire length.
