Growth control and properties of microcrystallized silicon films deposited by hydrogen plasma sputtering

In this work, optical and electrical properties have been correlated to the degree of crystallization of silicon films deposited by sputtering in a pure H 2 plasma at various substrate temperatures, T s. On increasing T s from 50 °C to 250 °C, the average grain size is found to grow from about 5 nm to some tens of nanometers, with a concomitant decrease of the optical band gap from 2.40 eV to 1.95 eV. The detection of photoluminescence emission in the visible region for the lowest T s seems to originate from the quantum confinement mechanism occurring in nanosized grains, whereas the conductivity increases by more than six orders of magnitude when T s is increased from 50 °C to 250 °C.