NONCONTACT THICKNESS AND COMPOSITION ASSESSMENT OF A STRAINED ALGAAS ALAS/INGAAS DOUBLE-BARRIER MULTIPLE-QUANTUM-WELL STRUCTURE/

By using a contactless double crystal x-ray diffraction technique with either photoluminescence or infrared intersubband absorption and theo retical calculations, it is possible to determine the dimensions and c omposition of a three layered multiple quantum well (MQW) structure ac curately. A strained AlGaAs/AlAs/InGaAs double barrier (DB) three laye red MQW structure was used to demonstrate this. Moreover, it is shown that this structure is well suited for infrared photodetection in the 3 mu m wavelength region, based on intersubband absorption. The compos itions and thicknesses evaluated are in good agreement, and transmissi on electron microscopy is utilized to confirm the thicknesses. (C) 199 6 American Institute of Physics.