CHARACTERIZATION OF MOVPE GROWN INPSB INAS HETEROSTRUCTURES/

InPSb was grown by low pressure metal-organic vapour phase epitaxy (LP -MOVPE) on InAs at temperatures between 520 degrees C and 570 degrees C. The samples were analysed by Raman and photoluminescence (PL) spect roscopy and high resolution X-ray diffraction (XRD). XRD as well as PL spectroscopy demonstrate the high quality of the deposited material. Sb contents of x = 0.31-0.34 in InP1-xSbx were investigated and lattic e matching on InAs was achieved as controlled by XRD. Raman spectra of micron thick InPSb layers display InSb-like and InP-like phonon featu res and an additionally weak structure related to liberated Sb. p-type doping of the InPSb with diethylzinc or H2S causes a change of the la ttice constant as indicated by XRD. The Raman spectra of the doped sam ples reveal changes in the lineshape of especially the InP-like phonon structure. Moreover, these changes differ for n- and p-type doping, w hich is interpreted in terms of free carrier contributions to the spec tra via plasmon-phonon coupling. The predicted miscibility gap and its consequences for future opto-electronic applications are discussed wi th respect to the growth conditions and the doping. (C) 1998 Elsevier Science B.V.