**What is amorphous silicon (a-Si)?** a-Si is *a commonly used TFT technology.* > **What are the three classifications of Thin Film Transistors (TFTs) depending on their material properties?** > Depending on their material properties, TFTs can be classified as: > * Amorphous silicon (a-Si). > * Low-Temperature Polycrystalline Silicon (LTPS). > * Oxide. **What does the term "amorphous" refer to?** The term "amorphous" refers to *a non-crystalline solid.* > **How are the atoms arranged in a non-crystalline solid?** > In a non-crystalline solid, the atoms are arranged *in a disorderly manner.* **What are three reasons why amorphous silicon (a-Si) was widely used?** Three reasons why a-Si was widely used are: 1. They're easy to manufacture. 2. They're easy to achieve screen uniformity with. 3. They're suitable for large displays. **What is the limitation of amorphous silicon (a-Si) and what causes it?** The limitation of a-Si is *it's low electron mobility caused by the fact that its atoms are disordered.* > **How does low electron mobility affect signal transmission?** > Low electron mobility affects signal transmission *by making it slower and less efficient.* > > **Was the limitation with using amorphous silicon (a-Si) a problem for early, low-resolution displays?** > *No*, the limitation with using amorphous silicon (a-Si) wasn't a problem for early, low-resolution displays. **What was developed to address the limitation of amorphous silicon (a-Si)?** To address the limitation of a-Si, *LTPS* was developed. > **How is Low-Temperature Polycrystalline Silicon (LTPS) made?** > LTPS is made *by using a laser to convert the disordered a-Si into ordered polycrystalline silicon at low temperatures.* **What is the diagram for the difference between the crystal structure of amorphous silicon (a-Si) and Low-Temperature Polycrystalline Silicon (LTPS)?** The diagram for the difference between the crystal structure of a-Si and LTPS is: