Gas collisions and pressure quenching of the photoluminescence of silicon nanopowder grown by plasma-enhanced chemical vapor deposition

The quenching of the photoluminescence of Si nanopowder grown by plasma-enhanced chemical vapor deposition due to pressure was measured for various gases ~ H2, O2, N2, He, Ne, Ar, and Kr! and at different temperatures. The characteristic pressure, P0, of the general dependence I(P) 5 I0 exp( 2 P/P0) is gas and temperature dependent. However, when the number of gas collisions is taken as the variable instead of pressure, then the quenching is the same within a gas family ~monoor diatomic! and it is temperature independent. So it is concluded that the effect depends on the number of gas collisions irrespective of the nature of the gas or its temperature. © 1997 American Institute of Physics. @S0021-8979~97!01207-3#