thus improving their efficiency by lowering resistance. Although this is an effective method, it causes the thermal component to under-perform compared to a solar thermal collector. Recent research showed that a-Si:H PV with low temperature coefficients allow the PVT to be operated at high temperatures, creating a more symbiotic PVT system and improving performance of the a-Si:H PV by about 10%. Thin-film-transistor liquid-crystal display Amorphous silicon has become the material of choice for the active layer in thin-film transistors (TFTs), which are most widely used in large-area electronics applications, mainly for liquid-crystal displays (LCDs). Thin-film-transistor liquid-crystal display (TFT-LCD) show a similar circuit layout process to that of semiconductor products. However, rather than fabricating the transistors from silicon, that is formed into a crystalline silicon wafer, they are made from a thin film of amorphous silicon that is deposited on a glass panel. The silicon layer for TFT-LCDs is typically deposited using the PECVD process. Transistors take up only a small fraction of the area of each pixel and the rest of the silicon film is etched away to allow light to easily pass through it. Polycrystalline silicon is sometimes used in displays requiring higher TFT performance. Examples include small high-resolution displays such as those found in projectors or viewfinders. Amorphous silicon-based TFTs are by far the most common, due to their lower production cost, whereas polycrystalline silicon TFTs are more costly and much more difficult to produce. See also Atomic layer deposition (ALD) Chemical-mechanical planarization (CMP) Chemical vapor deposition (CVD) Crystalline silicon Ion implantation Nanoparticle Physical vapor deposition (PVD) Protocrystalline Rapid thermal processing (RTP) References External links Amorphous Silicon Devices group at the University of Waterloo, Ontario, Canada Theory and Simulation at Ohio University, Athens Ohio Silicon forms Silicon, Amorphous Amorphous solids Thin-film cells