Infrared photoluminescence from Er doped porous Si

Intense infrared photoluminescence with the characteristic maximum at about 1.55 μm 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 °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 °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.