Metastability in tritiated amorphous silicon

The photoluminescence of tritiated, hydrogenated amorphous silicon films was studied as a function time. The samples were deposited over two years prior and tritium decay had resulted in more than 10²⁰ cm^-3 dangling bonds being created in the material. Consequently, photoluminescence was not present. Annealing for 1 h at 150 °C resulted in essentially all dangling bonds being pacified and the photoluminescence being restored. The luminescence decayed to a low value in 2 weeks. Subsequent annealing led to the recovery of the luminescence. The annealing process involves hydrogen diffusion and material reconstruction. The activation energy for the annealing process was found to vary with microstructure with increasing presence of clustered monohydrides leading to a lowering of the activation energy.