A comparison of the photoluminescence decay of erbium in silicon and silicon-germanium

Photoluminescence decay times have been measured from n- and p-type silicon, a Si/Si1−xGex (x=13%) multi quantum well structure, all implanted with Er, and a Si/Si1−xGex (x=25%) MQW structure uniformly doped with Er during MBE growth. The decaying PL signal is recorded using a signal-averaging transient capture card, and decays over nearly three decades are acquired with a system response time of 10 μs. The Er luminescence is much more intense in the Si/SiGe MQW structures than in silicon hosts. The method of Er-doping in the Si/SiGe heterostructures does not alter the PL decay significantly, but only one component is observed in the decay transient from the Er doped SiGe structures, compared with two in the PL decay of Er doped Si.