Efficient indirect-exciton luminescence in silicon nanowires

We have studied the near-infrared photoluminescence (PL) spectrum and dynamics in crystalline silicon nanowires with a triangular cross-section of about View the MathML source side length. Time-resolved PL measurements clearly show that the nanowire has a shorter PL lifetime than bulk crystalline silicon. The PL decay curve of the nanowire consists of the fast and slow components. The temperature dependence of the fast component intensity agrees with that of the integrated PL intensity. This agreement suggests that non-radiative recombination is suppressed in the nanowire. The short PL lifetime and no significant thermal quenching of the PL intensity result in the enhancement of the radiative recombination in the nanowire.