Abstract
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.
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