Polycrystalline GaAs Made by Selective Deposition and Its Optical Properties

Polycrystalline GaAs was grown by selective deposition using metalorganic chemical vapor deposition. The nucleation of polycrystalline GaAs took place on a small seed of polycrystalline Si on the substrate and overgrowth proceeded to SiO2 which covered the substrate. The photoluminescence (PL) intensity from polycrystalline GaAs was in inverse proportion to the seed size. When the seed size was 1 µm2, the PL intensity became six times larger than that for the polycrystalline GaAs on the seed size of 64 µm2. We fabricated a light-emitting diode (LED) on the amorphous substrate (SiO2) using polycrystalline GaAs deposited on the 1-µm2-area seed.