Formation of Built-in Light-emitting Junctions in Solution-grown GaP Containing Shallow Donors and Acceptors

The growth of GaP from a gallium-rich solution is described and the morphology and dendritic growth habit of the crystals are discussed. By control of growth conditions it was possible to produce built-in junctions in crystals doped with the shallow donors, S, Se, or Te, and the shallow acceptor, Zn. Green junction electroluminescence of higher efficiency than has been reported heretofore was observed from these structures. The effective segregation coefficients for the above impurities in GaP were determined by radiochemical techniques. On the basis of differences existing between these coefficients for the donor and acceptor dopants, and with the assumption of a two-step growth process, a mechanism for the formation of the junctions during precipitation of the crystals from solution is set forth.