High-Quality GaAsxP1-x/In0.13Ga0.87P Quantum Well Structure Grown on Si Substrate with a Very Few Threading Dislocations

Abstract

We proposed a novel quantum well (QW) structure of GaAsxP1-x/In0.13Ga0.87P grown on a GaP/Si substrate with a small lattice mismatch (1.4%) to the Si substrate, for a highly reliable laser diode (LD) on a Si substrate, and attempted to form the structure with a GaAs0.68P0.32 well and GaAs0.27P0.73 guiding layers. A two-dimensional (2D) growth mode was maintained during the growth of all layers. A cross-sectional image taken by transmission electron microscopy (TEM) revealed that the density of threading dislocations is the lowest in light-emitting device structures grown on Si substrates, as far as we know. The lattice mismatch of 1.4% was accommodated at the In0.13Ga0.87P-GaP and the GaP-Si heterointerfaces by introducing misfit dislocations. The quality and structural profile of GaAsxP1-x epilayers was improved by varying the As4 flux in a short period. As a result, strong band-edge emission was observed from the GaAs0.68P0.32 QW at room temperature (RT). It was also found by secondary-ion mass spectroscopy (SIMS) that relatively abrupt heterointerfaces were formed in the QW structure of GaAs0.68P0.32/GaAs0.27P0.73/In0.13Ga0.87P.