A light emitting and detecting device and a method of manufacturing the same are provided. The method includes forming an insulating layer on a substrate doped with an n-type dopant or a p-type dopant, and removing a portion of the insulating layer to expose a predetermined area of the substrate; forming a doping layer doped with an opposite dopant to the dopant of the substrate by applying a dopant on the exposed area of the substrate and heat treating the substrate to create a light conversion effect in a p-n junction between the substrate and the doping layer; and forming first and second electrodes on the substrate to electrically connect the doping layer. Thus, it is possible to control the diffusion depth of the doping layer with opposite dopant to the substrate in the substrate.