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GaAsP/Si with high crystalline quality fabricated by cost‐effective heteroepitaxial technology is a promising pathway for realizing low‐cost Si‐based tandem solar cell with efficiency higher than 30%. Herein, hydride vapor‐phase epitaxy is used to perform selective area growth of GaAsP with high lateral coverage, referred to as epitaxial lateral overgrowth (ELOG). The ELOG is performed on GaAs‐based substrates as a prestudy, followed by GaAs/Si and GaAsP/Si seed wafers employing chemical mechanical polishing to fabricate full 2″ GaAsP/Si templates. These are subsequently used to grow and process GaAsP/Si pn‐junction structures for electrical characterization. The ELOG GaAsP is studied by spatially resolved photoluminescence (PL) mapping and high‐resolution X‐ray diffraction measurements. PL analysis of the GaAsP/GaAs ELOG samples reveals an enhanced P‐incorporation during lateral growth of GaAsP. This is also observed for the GaAsP/Si ELOG templates along with evidence of improved material quality, clearly distinguishing the laterally grown GaAsP from the planar growth directly above the Si substrate. Leakage pathways causing reduced electrical performance of the ELOG GaAsP/Si pn‐junction structures are identified. [ABSTRACT FROM AUTHOR]

The growth of GaInP by hydride vapor phase epitaxy (HVPE) was studied on planar GaAs, patterned GaAs for epitaxial lateral overgrowth (ELOG), and InP/Si seed templates for corrugated epitaxial lateral overgrowth (CELOG). First results on the growth of direct GaInP/Si heterojunction by CELOG is presented. The properties of Ga xIn(1 − x)P layer and their dependence on the process parameters were investigated by X-ray diffraction, including reciprocal lattice mapping (XRD-RLM), scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDS), photoluminescence (PL), and Raman spectroscopy. The fluctuation of Ga composition in the Ga xIn(1 − x)P layer was observed on planar substrate, and the strain caused by the composition variation is retained until relaxation occurs. Fully relaxed GaInP layers were obtained by ELOG and CELOG. Raman spectroscopy reveals that there is a certain amount of ordering in all of the layers except those grown at high temperatures. Orientation dependent Ga incorporation in the CELOG, but not in the ELOG Ga xIn(1 − x)P layer, and Si incorporation in the vicinity of direct Ga xIn(1 − x)P/Si heterojunction from CELOG are observed in the SEM-EDS analyses. The high optical quality of direct GaInP/Si heterojunction was observed by cross-sectional micro-PL mapping and the defect reduction effect of CELOG was revealed by high PL intensity in GaInP above Si. [ABSTRACT FROM AUTHOR]