Microwave plasma-enhanced chemical vapour deposition (MW PE CVD) growth conditions for preparation of polycrystalline phosphorous-doped diamond layers are presented. The incorporation of substitutional phosphorous was confirmed by low temperature photocurrent (PC) and cathodoluminescence (CL) measurements. The topographical characteristics of thefilms and the relation between the substrate and P-dopedfilm grain orientation were studied by scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD). The growth process for P-doped layers on (110) oriented polycrystalline diamond was optimised and the best set of parameters differs significantly from the standard conditions used for P-doping of single crystalline (111) oriented diamond surfaces. (c) 2008 Elsevier B.V. All rights reserved.