Excitonic sensor of electric field in quantum-well heterostructures

We present an experimental and theoretical study of the lowest exciton states in a 30-nm single GaAs quantum-well heterostructure in different electric fields. We found that the excitons in quantum wells are highly sensitive to an electric field and demonstrate nonlinear behavior in terms of their energy position, amplitude, spectral width, and phase of exciton resonances in reflection spectra. Comparison of experimental results with theoretical calculations allowed us to reliably determine the electric field strength in the quantum-well layer.