The thin-film transistors which drive the individual cells in the overlying liquid crystal layer in traditional active-matrix displays are formed from amorphous silicon (a-Si) deposited on a glass substrate. The advantage of using amorphous silicon is that it doesn't require high temperatures, so fairly inexpensive glass can be used as a substrate. A disadvantage is that the non-crystalline structure is a barrier to rapid electron movement, necessitating powerful driver circuitry.
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