Using high-resolution imaging technology, University of Illinois researchers have answered a question that had confounded semiconductor researchers: Is amorphous silicon a glass? The answer? Yes – until hydrogen is added. Led by chemistry professor Martin Gruebele, the group published its results in the journal Physical Review Letters (“Direct Imaging of Two-State Dynamics on the Amorphous Silicon Surface”). Amorphous silicon (a-Si) is a semiconductor popular for many device applications because it is inexpensive and can be created in a flexible thin film, unlike the rigid, brittle crystalline form of silicon. But the material has its own unusual qualities: It seems to have some characteristics of glass, but cannot be made the way other glasses are.
