Polycrystalline silicon recombination

Similar passivation effects of atomic hydrogen on grain boundaries in polycrystalline silicon have also been reported (39). However, the explanation here is that the surface or grain boundary states are filled upon interaction with covalently bonding atoms, and these filled states then become inactive as recombination centers. Further work is required to establish the correct model. 

The specific application of a material generally determines the particular structure desired. For example, hydrogenated amorphous silicon is used for solar cells and some specialized electronic devices (10). Because of their higher carrier mobility (see Carrier Transport, Generation, and Recombination), single-crystalline elemental or compound semiconductors are used in the majority of electronic devices. Polycrystalline metal films and highly doped polycrystalline films of silicon are used for conductors and resistors in device applications. 

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