The invention relates to a semiconductor layer material, in particular for use as an emitter material for a heterojunction solar cell, formed as a stack of a plurality of first and second layers each arranged in alternation one over the other, wherein the first layers comprise an elementary, polycrystalline semiconductor and the second layer comprises a substochiometric, electrically insulating compound, particularly an oxide, carbide or nitride, of the semiconductor and wherein the bordering surfaces between the first and second layers are irregularly structured by a tempering such that micro contact regions are formed between neighboring first layers separated from each other by a second layer.