1D photonic band gap PbTe doped silica quantum dot optical device

Thin films of glass doped with PbTe quantum dots (QDs) were successfully fabricated. The semiconducting nanocrystallites were grown by laser ablation of a PbTe target (99-99%) using the second harmonic of a Q-Switched Quantel Nd: YAG laser under a high purity argon atmosphere. The glass matrix was fabricated by a plasma chemical vapour deposition method using tetramethoxysilane (TMOS) vapour as precursor. The QDs and the glass matrix were alternately deposited onto a Si (100) wafer for 60 cycles. A cross sectional TEM image clearly showed the QD layers well separated from each other by glass matrix layers. The influence of the ablation time and the laser fluence on the density and size distribution of the quantum dots was studied. HRTEM revealed anisotropy in the size of the QDs: they were about 9 nm in height and 3-5 nm in diameter. Furthermore HRTEM studies revealed that the QDs basically grew in the (200) and (220) directions. The thickness of the glass matrix layer was about 20 nm. Absorption, photoluminescence and nonlinear optical properties of the device are currently being measured.