DESIGN AND FABRICATION OF ASYMMETRIC STRAINED-LAYER MIRRORS FOR OPTOELECTRONIC APPLICATIONS

The design of thin-film mirrors is optimized for strained layer materi als systems. It is shown that the use of asymmetric structures produce s only minor loss in reflectivity per mirror period, while greatly ext ending the number of periods that can be grown in a defect-free mode. As applied to the GexSi1-x/Si strained layer system, the net result is an enhancement of reflectivity, with 1.3 mum mirrors achieving peak v alues near 75%. The approach is applicable to other materials systems and should yield even higher reflectivities in situations where wider ranges in index of refraction are available.