Study of optical properties of GeO_2 nanocrystals as synthesized by hydrothermal technique

摘要

The GeO_2 nanocrystals (α-quartz type structure) with β-phase are synthesized at relatively lower temperature by hydrothermal route using autoclave. All samples are characterized by XRD, FESEM, EDS, TEM, photoluminescence (PL) and UV-vis absorption spectroscopy techniques. Synthesized nanocrystals have uniform shape and uniform size distribution for a particular synthesis condition, which is about 30-300 nm depending on synthesis conditions. The XRD results indicate that grown GeO_2 crystals only shows peak related to α-quartz structure with lattice parameters α - 4.985 A and c = 5.648 A. UV-vis absorption spectroscopy measurements reveal the bandgap energies corresponding to the GeO_2 α-quartz structure. Synthesized nanocrystals are capable to emit strong blue light around 425-435 nm under excitation of 300 nm and 325 nm and consequently the as synthesized material can be used in integrated optical devices.