Sunday, July 3, 2016

Research: AlN Nanopowder Spectral Characterization

From now, you will be able to follow series of articles about topical researches done by our UL SPIE Student chapter's members. We are eager to offer news and feature stories covering all fields of science, especially optics and photonics, technology, engineering and math in order to encourage promising young scientists to launch their successful careers: from small discoveries to great victories. 
Let us start with our member, physicist Bc.Sc. Paula Jankovska who had been working with aluminium nitride nanopowder spectral characterization (supervisor:  Dr. habil. Baiba Berzina); and learn more about her novel investigations.

Aluminium nitride nanopowder

To start with, AlN nanopowder spectral characteristics are explored in the scientific work, 420 nm luminescence band and its luminescence melumichanism were investigated. Nanopowder was synthesized in the Riga Tehnical University, Institute of Inorganic Chemistry, spectral analysis was done in University of Latvia Institute of Solid State Physics Laboratory of Wide Band Gap Materials.

Excitation of aluminium nitride (AlN) in 265 nm area
Wide luminescence band and its excitation spectrum in 420 nm area was investigated, it was concluded that 420 nm luminescence band main excitation light wave lengths are 265 nm and 315 nm. 420 nm luminescence bands luminescence dependence on temperature is measured, so defects energy level arrangements in energy band gap and luminescence mechanism could be understood.

Excitation of AlN in 315 nm area
Also, 420 nm luminescence bands sensitivity to gases that air contains was examined and investigated. It was clarified that AlN nanopowders 420 nm luminescence band is sensitive specifically to oxygen that is containd in air. Oxygen gas dosimetry was made with different oxygen gas concentrations - 2%, 5%, 10%, 21%, 50% and 100%. Measurement repeatability, which is an important property for prospective application of the material in optical gas detectors, was tested. It was found that AlN nanopowders 420 nm luminescence band is sensitive to different oxygen concentrations in environment and measurement repeatability is good.

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