Layered germanium polymers that are semiconductive and demonstrate a strong red or infrared luminescence are produced through the topochemical conversion of calcium digermanide. Furthermore, silicon/germanium layer polymers can also be produced in this manner. These layer polymers can be produced epitaxially on substrates comprising crystalline germanium, and can be used to construct light-emitting optoelectronic components such as light-emitting diodes or lasers.