A far infrared modulated photoluminescence (FlRM-PL) study of cyclotron resonance in a 2D electron gas in GaAs/AI_xGa_(1-x)As heterojunctions

摘要

The new technique of far infrared modulated photoluminescence(FIRM-PL) has been used to study the properties of a high mobility 2Delectron gas in a series of GaAs/AlGaAs heterojunctions. When theoccupancy of the lowest Landau level is between 1 and 2 very largetransfers of PL intensity are observed at the cyclotron resonancecondition. The PL intensity is transferred from the E_0 line to E_1corresponding to emission from the first two quantized electricsubbands. A study of the power dependence of this signal allows us todeduce that the relative recombination efficiencies of the two linesare around five orders of magnitude different in such structures.This difference leads to a very high sensitivity of this techniquefor the observation of internal excitations within the electronsystem.