Reduction in surface recombination of GaInAsP microcolumns by CH4 plasma irradiation

We evaluated the surface recombination velocity v(s) of 1.55 mum GaInAsP microcolumns through the measurement of carrier lifetime using the phase-resolved spectroscopy. We investigated various surface treatments and confirmed that v(s) was reduced to nearly half of that for as-etched microcolumns by CH4 electron cyclotron resonance plasma irradiation. This result was ensured by the two- to fivefold increase in photoluminescence intensity. The secondary ion mass spectroscopy analysis suggested that the reduction in v(s) was attributable to the deposition of a polymer, the hydrogenated hard carbon, etc., and/or a carbon deep level formed near the surface. (C) 2001 American Institute of Physics.