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 differen t controlled porosity were fabricated by electrochemical anodization of n a nd p Cz-Si wafers as well as at p+/n silicon junction. Er was introduced in to the porous Si using a spin-on doping technique. Rutherford backscatterin g spectroscopy measurements show that annealing up to 1000 degrees C does n ot influence the Er depth distribution in the porous silicon, although it s trongly influences the oxygen content of the Si skeleton and the ErIR PL in tensity. 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 implan ted and annealed porous Si layers. It was found that a strong ErIR PL inten sity was only observed in the spin-on-doped porous Si layers formed on p an d p+/n substrates, which exhibit, simultaneously, an intense PL intensity i n the visible range. The mechanism of Er related IR luminescence in porous silicon is discussed. (C) 2000 American Institute of Physics. [S0021-8979(0 0)02311-2].