Giant electrooptical effect on [formula omitted] doped QW structures

Abstract

Waveguide optical absorption, electroabsorption, and photocurrent spectra were studied at room temperature in a p-n heterostructure with a modulation doped GaAs QW placed in the n-doped region. The measured photocurrent spectra permit one to determine the two-dimensional electron concentration N s as function of the external bias voltage. It has been found that the observed large red shift of the optical absorption edge due to the bias voltage results mainly from a Burstein-Moss shift at high concentration N s and from a Stark shift of confined states at low N s.