One way to do this is called a remote epithetic, where an intermediate layer made of graphine or other materials is introduced between the substrate and the growing crystal. Once the epilepsy process is completed, the substrate and everything that is on it is soaked in a chemical solution that dissolves the intermediate layer, which maintains the crystal film. It works but is expensive, the scale is difficult, and takes a lot of time. To make this process cheaper and faster, the MIT team had to grow crystals directly on the substitute without any intermediate layer. What they were trying to get was a non -stick frying pan effect but atomicly small scale.
To weaken bonds
The content that prevented crystal films from being based on substrates was not a taflon but a lead. When the team was experiencing increasing various films in its previous studies, they found that there was a material that easily comes out of the substrate, still maintains a smooth surface: PMN-PT, or lead magnesium Nobett Titanit.
Lead atoms in PMN-PT weakened the harmony bonds between the film and the substrate, which prevented the electrons from jumping into the interface between the two materials. Zhang told ARS, “We had to create a little stress to create a crack in the interface between the film and the substrate and we could feel the elevator.” “Very easy – we can remove these movies in a second.”
But the PMN-PT, in addition to its hereditary instability, had more tricks in its sleeves. It had extraordinary pyro electric properties. Once the team realized that they could prepare and spark the PMN-PT films, they made a lot of complicated efforts: cooling-free, far-flung radiation detection. “We were trying to achieve comparative performance with a cold detector,” says Zhang.
The detector he built was made of 100 pieces of 10 nanometer thin PMN-PT films, about 60 square microns each, which the team moved to the silicon chip. He manufactured 100 pixel infrared sensors. Tests, with everlasting small changes in temperature, indicated that it improved the latest night vision system and was sensitive to radiation throughout the infrastructure spectrum. (Mercury cadmium teloride detectors respond to a very narrow band of wavelengths.)