Experimental Evidences of Bias Driven, Spatially Delocalized, Inverted Dipoles of 2D Indirect Excitons using Photocapacitance at Room Temperature

摘要

In this work, we show that inverted dipoles of two dimensional, indirectexcitons in a GaAs/AlAs/GaAs single barrier p-i-n structure can be probed byphotocapacitance at room temperature. Photocapacitance signal of resonantlysharp excitonic absorption peak follows the areal density of these indirectexcitons which decrease with tunnelling at higher biases. UnlikeDC-photocurrent spectra, photocapacitance spectra red shift, sharpen up withincreasing applied electric field. Such dissimilarities could be used toselectively tune indirect excitons having large effective dipole moments fornovel device applications.