Evaluation of erbium-doped silicon for optoelectronic applications

TLDR

The study aims to determine the performance limits of erbium‑doped silicon as LEDs, amplifiers/modulators, and lasers, and to outline future research directions. The authors conduct best‑case feasibility evaluations using physics‑based intrinsic parameters, avoiding material‑quality dependencies. The feasibility study finds that Er‑doped Si is unsuitable for LED use due to microwatt‑level emission, offers only modest (<6 cm⁻¹) amplifier/modulator gain, can theoretically reach laser threshold but requires highly efficient pumping for milliwatt‑level output, and that these conclusions likely extend to other rare‑earth‑doped semiconductors.

Abstract

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, amplifiers/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 (&amp;lt;6 cm−1). For laser applications, the threshold population inversion can be achieved 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.