EVALUATION OF ERBIUM-DOPED SILICON FOR OPTOELECTRONIC APPLICATIONS

Best-case evaluations are made for potential optoelectronic applications of erbium-doped silicon (EDS). The objective is to find the upper limit of performance when EDS is used as light-emitting diodes, amplifers/modulators, and lasers. Every effort is made to use intrinsic parameters whose values are determined by physics rather than by factors such as material quality and processing quality. Consequently, the result is expected to be overly optimistic, and should be regarded as a feasibility study only. It is shown that Er-doped Si is not suitable for light-emitting-diode applications because of the low emitted power (microwatts). The intensity amplifiers/modulators made of Er-doped Si can only be expected to provide a very modest gain ( < 6 cm-1). For laser applications, the threshold population inversion can be archieved in principle (assuming proper design and processing of the laser structure); however, a very efficient pumping mechanism is necessary for the laser to provide reasonable power output (of the order of mW/facet). Finally, a view on the direction of future research in this field is presented. Since the rare-earth ion luminescence is known to be fairly independent of the host materials, the results obtained from this study are expected to be applicable to most of the other rare-earth-doped semiconductors.