Dopant compositions comprising a semiconductor material are described. Examples of dopant compositions comprise a particulate dopant component and a liquid or paste component, or comprise a dopant component and a particulate silicon component. Methods of forming doped regions in a semiconductor substrate material using the dopant compositions are described. A dopant composition including a dopant particulate component is described as a dopant source in a method for the formation of radiation-fired or radiation-doped contacts, for example in the formation of laser-fired or laser-doped contacts. Examples of the method find application in relation to the manufacture of photovoltaic cells. The use of doped particulate material, for example a composition including doped silicon powder, may reduce the likelihood of damage to the substrate.
 The United States Government has rights in this invention under Contract No. DE-AC36-08GO28308 between the United States Department of Energy and the Alliance for Sustainable Energy, LLC, the Manager and Operator of the National Renewable Energy Laboratory.