Controllable red and blue bandgap energy shifted LEDs and modulators on InGaAsP quantum well platform

Abstract

Exploiting a controllable technique for red and blue shifting of quantum well’s bandgap energy, we have fabricated LED sources accessing a wide frequency spectrum along with all-optical intensity modulator devices. . We demonstrate bandgap tuning of InGaAsP multiple quantum well structures by utilizing an impurity free vacancy diffusion technique. Substantial modification of the bandgap energy toward the red and blue part of the spectrum has been observed using SiO2 , SiOyNx , SiNx capping layers and by controlling the associated oxygen and nitrogen content. The resulting degree of tuning, up to 120nm red-shift and 140nm blue-shift of the band to band wavelength emission, has been studied using room temperature photoluminescence, in agreement with the emission spectra obtained from semiconductor LED devices fabricated on this platform. The intensity modulator devices has been fabricated along with LED sources compatible for the selected frequency, designed to reach minimum material losses and residual amplitude modulation.