The growth of a GaP 50 nm layer on Si by metalorganic vapor phase epitaxy is studied using AsH3 and PH3 pre-exposure at low (550 degrees C) and high (800 degrees C) growth temperatures. The samples are characterized by transmission electron microscopy. The results obtained reveal that the use of As as a first coverage layer on top of misorientated Si-substrates favors the formation of a defect-free GaP epitaxial layer, for a wide range of AsH3 pre-exposure times using high growth temperature (800 degrees C), even though relatively low Si substrate annealing temperatures are used (850 degrees C) and no homoepitaxial Si layer was first grown. The procedure presented in this work reduces the thermal budget and complexity compared to most previous GaP/Si routines.