Direct growth of GaP on Si enables the integration of III-V and Si optoelectronic devices for a wide variety of applications, and has therefore been the subject of much research for many decades. Most of this effort has been directed toward overcoming the two main technical challenges: 1) removing atmospheric oxygen and carbon contamination and 2) establishing the conditions needed for "APD-free" III-V epitaxy (i.e., without antiphase domains). We have developed an OMVPE process for APD-free GaP growth on Si which overcomes both challenges by using AsH3 to clean and prepare the Si surface in situ at a relatively low temperature. This process is based upon a very brief "AsH3-cleaning" step which simultaneously removes atmospheric contamination (thereby eliminating the need for Si regrowth) and creates a single domain As-terminated Si surface. Here we discuss the key process steps using results from a suite of analysis tools. Published by Elsevier B.V.