- A crystalline material in which there is short-range order. The overall crystalline structure is composed of highly-ordered units, with grain boundaries between individual crystals. A single-crystal material (1) has no such boundaries, so there is complete uniformity over the entire crystal. The grain boundaries decrease the efficiency of any semiconductor device consisting of a polycrystalline material. Used, for instance, as semiconductor materials which do not have to be of the highest quality.
- A crystalline material consisting or more than one type of crystal.