Infrared photoluminescence from Er doped porous Si

Intense infrared photoluminescence with the characteristic maximum at about 1.55 mu m was observed at room temperature in Er-doped porous silicon [Er related infrared photoluminescence (ErIR PL)]. Porous Si layers of different controlled porosity were fabricated by electrochemical anodization of n and p Cz-Si wafers as well as at p+/n silicon junction. Er was introduced into the porous Si using a spin-on doping technique. Rutherford backscattering spectroscopy measurements show that annealing up to 1000 degrees C does not influence the Er depth distribution in the porous silicon, although it strongly influences the oxygen content of the Si skeleton and the ErIR PL intensity. For the spin-on-doped samples annealed at 1000 degrees C, the ErIR PL intensity is increased by two orders of magnitude compared to Er implanted and annealed porous Si layers. It was found that a strong ErIR PL intensity was only observed in the spin-on-doped porous Si layers formed on p and p+/n substrates, which exhibit, simultaneously, an intense PL intensity in the visible range. The mechanism of Er related IR luminescence in porous silicon is discussed. (C) 2000 American Institute of Physics. [S0021-8979(00)02311-2].