Modulation spectroscopic approach to the study of photocurrent spectra in GaAs/GaAlAs QW-GRIN laser structures

摘要

Abstract: The current transport through GaAs/GaAlAs quantum wellgraded index (QW GRIN) injection lasers was studied byphotocurrent spectroscopy. The quantum efficiency isassumed to be proportional to the absorptioncoefficient. The observed absorption edges areattributed to transitions between different QWsubbands. Measurements have been carried out withtransverse electric (TE) and transverse magnetic (TM)light polarization in order to study the anisotropy duetot eh quantum well and the influence of the GRINwaveguide. Different spectroscopic modes have beencompared, among them a setup with rotating polarizer.After background subtraction the observed edges can becompared with existing theories. The factors affectingthe lineform are outlined. !12