HIGH-RESOLUTION X-RAY-DIFFRACTION STUDY OF PIEZOELECTRIC INGAAS GAAS MULTIQUANTUM-WELL P-I-N PHOTODIODES GROWN ON (111)B GAAS/

High-resolution x-ray diffractometry has been applied to the structura l characterization of piezoelectric strained InGaAs/GaAs multiquantum well p-i-n diodes grown by molecular beam epitaxy on (111)B GaAs subst rates. Reference samples simultaneously grown on (001) GaAs have been also characterized. Diodes with 3, 7, and 10 periods and different wel l to barrier thickness ratio have been studied. Symmetric and asymmetr ic reflections at various azimuths were measured and the scans were fi tted with theoretical curves obtained through a dynamical simulation p rogram developed in our lab. The comparison between experimental and s imulated profiles has enabled us to determine the main structural para meters of the samples. High-resolution x-ray diffractometry provided a ccurate data about period and capping layer thicknesses, indium conten t in the wells and state of relaxation, information which cannot be al ways obtained in (111)B samples from other characterization techniques such as photoluminescence or photocurrent spectroscopies. (C) 1996 Am erican Institute of Physics.