Room-temperature electroluminescence from erbium-doped porous silicon

We demonstrate stable room-temperature electroluminescence (EL) at 1.54 mu m from erbium-doped porous silicon devices under both forward- and reverse-bias conditions. Erbium was infiltrated in the pores (less than or equal to 10(19) cm(-3)) by cathodic electrochemical migration of the ions followed by high-temperature annealing (950-1100 degrees C) in an oxygen and nitrogen environment. The devices exhibit an exponential EL dependence in both bias conditions as a function of input power. In reverse bias, the external quantum efficiency reaches 0.01%. The EL intensity decreases by a factor of 24 for reverse bias and 2.6 for forward bias when the temperature increases from 240 to 300 K. The different device characteristics in forward and reverse biases suggest that different excitation mechanisms are responsible for EL. (C) 1999 American Institute of Physics. [S0003-6951(99)04051-6].