Abstract: The invention relates to a semiconductor sensor device (10) for sensing a substance comprising at least one nanowire (11) which is formed on a surface of a semiconductor body (12) and which is connected at a first end to a first electrically conducting connection region (13) and at a second end to’ a second electrically conducting connection region (14) while a fluid (20) comprising a substance (30) to be sensed can flow along the nanowire (11) and the substance (30) to be sensed can influence’ the electrical properties of the nanowire (11), wherein the nanowire (11) comprises viewed in a longitudinal direction subsequently a first semiconductor subregion (1) comprising a first semiconductor material and a second semiconductor subregion (2) comprising a second semiconductor material different from the first semiconductor material. According to the invention’ the first semiconductor material comprises a IV element material and the second semiconductor material comprises a III-V compound.