Observation of quantum confined Stark effect in wider quantum wells by a novel photocurrent-difference spectroscopy

Photocurrent-difference spectroscopy has been applied to the determination of the interband optical transition energy in InGaAs/InAlAs multiquantum wells under Stark electric field. The photocurrents were measured using p-i-n junctions including quantum wells in the i-layer. By taking the difference of the two spectra at two different fields, vague photocurrent spectra in 20-nm-wide wells were changed into oscillatory spectra as a function of wavelength. The Stark shift of the peak energy over 43 meV was observed under -3 V bias or the Stark field of 93 kV/cm.