A series of variously doped liquid phase epitaxy (LPE) layers were analyzed to establish the distribution of Zn,O and residual impurities contributing to the net impurity gradient previously observed in the p‐layer of high efficiency LPE diodes. From these experiments we conclude that the net impurity gradient is primarily a consequence of a decreasing Zn concentration along the growth direction, and, to a lesser degree, an increasing residual donor concentration. The distribution of intentional and unintentional impurities was found to be independent of substrate doping level.