In one implementation, a substrate susceptor for receiving a semiconductor substrate for selective epitaxial silicon-comprising depositing thereon, where the depositing comprises measuring emissivity of the susceptor from at least one susceptor location in a non-contacting manner, includes a body having a front substrate receiving side, a back side, and a peripheral edge. At least one susceptor location from which emissivity is to be measured is received on at least one of the front substrate receiving side, the back side, and the edge. Such at least one susceptor location comprises an outermost surface comprising a material upon which selective epitaxial silicon will not deposit upon during selective epitaxial silicon depositing on a semiconductor substrate received by the susceptor for at least an initial thickness of epitaxial silicon depositing on said substrate. Other aspects and implementations are contemplated.