Well resolved, sharp photoluminescence (PL) peaks of Er3+ (4f(11)) ions at similar to 1.54 mu m are obtained from Er-doped porous silicon (PS:Er) on which a hydrogen plasma treatment is carried out after electrochemical incorporation of Er3+ ions into porous silicon. The full width at half maximum (FWHM) of the 1.538 mu m main peak at 20 K is less than 1 nm, which is much smaller than that obtained from PS:Er samples annealed in a H-2 or O-2 flow (FWHM 7-10 nm), and is comparable to that of Er-doped crystalline silicon. The thermal quenching of the PL intensity is, however, relatively small, the PL intensity decreasing only by a factor of 10 from 20 to 300 K. (C) 1998 American Institute of Physics. [S0021-8979(98)03114-4].