Ultraviolet electroabsorption modulator based on AlGaN∕GaN multiple quantum wells

An ultraviolet electroabsorption modulator based on AlGaN∕GaN quantum wells is demonstrated. Enhanced excitonic absorption in the quantum wells at around 3.48eV was achieved using a Schottky contact to partially cancel the polarization-induced electric fields in the quantum well layers. A change in the absorption coefficient greater than 4×104cm−1 was obtained for a modest reverse bias of 10V. The observed blueshift in the exciton energy was smaller than that predicted by theoretical calculations. This is accounted for by variations in the background carrier concentration in the wells with reverse bias.