Current modulated light reflectance spectroscopy with submicron spatial resolution in semiconductor heterostructures

We propose a new method of the optical spectroscopy of the semiconductor heterostructures. This technique is based on the effect of electron heating on a dielectric function ε(ω) of the structure for photon energy ℏω near fundamental gap of layers. For the electrons to be heated the alternating electric field is applied to ohmic contacts along heterostructure layers. As the current density is spatially inhomogeneous in heterostructures, the electron heating is also inhomogeneous. This results in the spatial redistribution of hot electrons in the direction perpendicular to layers. Two general mechanisms are responsible for modification of the reflected probe light spectrum being measured. One of them is appearance of transverse thermoelectric field that changes built-in electric fields. The second mechanism is effect of the hot electron on exciton binding energy.