A novel approach to the synthesis of photoluminescent germanium nanoparticles by reactive laser ablation

We propose a novel approach to the synthesis of photoluminescent Ge nanoparticles using reactive laser ablation. The deposition of germanium under low oxygen pressure (2–100 mTorr) yields Ge nanoparticles embedded in a Ge oxide matrix. Ge nanostructures were characterized by transmission electron microscopy, x-ray photoelectron spectroscopy and photoluminescence (PL) spectroscopy. The oxygen pressure determines the degree of oxidation of GeO x films (0≤ x ≤2). A strong PL signal depending on oxygen pressure was observed. The PL maximum is detected for 10 mTorr of oxygen corresponding to a nanoparticle size of 1.8 ± 0.5 nm.