Plasma Enhanced Atomic Layer Deposition of InP Layers and Multilayer InP/GaP Structures on Si Substrate

For the first time, InP layers were grown on Si substrates at a temperature of 380°C using the plasma-enhanced atomic layer deposition. According to X-ray diffraction analysis and transmission electron microscopy, the layers are microcrystalline with a grain size of 20–30 nm and a preferred orientation (111). Raman spectra exhibit clearly distinguish the LO peak at 341.9 cm–1, which is characteristic of crystalline InP. Microcrystalline InP layers grown on fused silica substrates demonstrated a high photoconductivity of 2.3 Ω–1 cm–1 under solar spectrum AM1.5G (100 mW/cm2) illumination. The study of the growth of layers of binary compounds InP and GaP in one process of plasma-enhanced atomic layer deposition demonstrated the fundamental possibility of controlling the composition of InP/GaP digital alloy. The InP/GaP digital alloys are characterized by the coalescence of the LO peaks of InP (341.9 cm–1) and GaP (365 cm–1) in the Raman spectra. Increase of GaP component in the layer leads to boarding of this feature in the Raman spectra due to a shift of the edge towards the GaP peak (402 cm–1). A study of the optical properties by transmission and reflection measurements of microcrystalline InP/GaP digital alloy layers deposited on transparent substrates demonstrated the possibility of varying the optical gap in the range of 1.3–2 eV.