Ultrafine Condensation Particle Counter Research Articles

Aerosol particles from metalorganic vapor phase epitaxy bubblers

We report on aerosol particles formed by bubbling a carrier gas through bubblers in metalorganic vapor phase epitaxy (MOVPE). A triethylgallium bubbler was investigated in a MOVPE set-up regarding the generation of aerosol. We measured particle number concentrations with an ultrafine condensation particle counter, which can detect submicrometer aerosol particles larger than 3 nm in diameter. We found that a standard triethylgallium bubbler used in a conventional way produces aerosol particles. The number of particles is a function of the carrier gas flow through the bubbler and correlates with the number of bubbles. The aerosol size distributions were analyzed with a differential mobility particle sizer and found to range from 10 to 600 nm, with maxima between 150 and 200 nm. Size distribution as well as total number of aerosol particles depend on evaporation processes during transport in undersaturated gas flows. While the number of particles reaching the reactor is not negligible, the precursor is predominantly transported as gas molecules. Particles can in principle, though, reach the substrate and create defects on the surface.

Intercomparison of Four Methods to Determine Size Distributions of Low-Concentration (∼ 100 cm−3), Ultrafine Aerosols (3 <Dp< 10 nm) with Illustrative Data from the Arctic

Four different methods for measuring ultrafine particle size distributions in the 3–10-nm particle diameter range are compared and discussed. These methods all use an ultrafine condensation particle counter (TSI Inc. Model 3025 or its prototype) as the detector, but use different approaches to determine the size of the particles counted. Size classification was achieved using a Hauke Model VIE-06 differential mobility analyzer, a specially configured TSI Model 3040S diffusion battery, an ultrafine condensation particle counter with a variable condenser temperature, and an ultrafine condensation particle counter with a pulse height analyzer for signals produced by the optical detector. The response of these systems to ultrafine particles of known size and composition was studied during a workshop held in Lund, Sweden, during July 1991. After this workshop, measurements of ultrafine particles were made on the Swedish icebreaker Oden during the International Arctic Ocean Expedition 1991 (August 1, 1991 throu...

Calibration of a TSI Model 3025 Ultrafine Condensation Particle Counter

The registration efficiency of the TSI model 3025 ultra-fine condensation particle counter for Ag and NaCl particles of between 2 and 20 nm in diameter was determined. Taking into account the different shapes of the input aerosol size distributions entering the differential mobility analyzer (DMA) and the transfer function of the DMA, the counting efficiencies of condensation nucleus counters (CNC) for monodisperse Ag and NaCl particles were estimated. In addition, the dependence of the CNC registration efficiency on the particle concentration was investigated.