Scanning electrical mobility

More dramatic improvements are obtained with the scanning electrical mobility spectrometer, which achieves better time resolution without sacrificing size resolution. 

Wang S. C., Flagan R. C. Scanning Electrical Mobility Spectrometer. Aero. Sci. Technol. 1990,13, 230-240. 

Next, the sampling flow was guided to different measurement instruments. The concentration number and the size distribution of submicron particles (0.01-0.5 pm) was obtained with a TSI Scanning Mobility Particle Sizer (SMPS) consisting of a differential electrical mobility analyzer coupled with a condensation nuclei counter. Previously a preconditioning gas system was used. This basically consists of a cyclon,... 

One potential method for measuring the size of aerosol nanoparticles is a scanning mobility particle sizer (SMPS), consisting of a differential mobility analyzer (DMA) and a condensation particle counter (CPC). Aerosol particles enter the DMA where they are charged using a radioactive source and their size is classified based on the electrical mobility, Z, of the particles in the applied electrical field ... 

Note DMS differential mobility spectrometer, SMPS scanning mobility particle sizer, CPC condensation particle counter, TDMPS twin differential mobility particle sizer, DMPS differential mobility particle sizer, OPC optical particle counter, APS aerodynamic particle sizer, MAS mass aerosol spectrometer, LAS-X optical laser aerosol spectrometer, ELPI electrical low pressure impactor... 

The ehapter is organised as follows. After the introduction, a brief overview of the fundamentals of CNTs and CNT-based FETs will be given. The next section describes a range of chemical functionalisation schemes that have been devised for the performance enhancement of CNT-FETs. The subsequent section is devoted to the characterisation of as-prepared and functionalised CNT-FETs through electrical transport measurements and scanning photocurrent microscopy. In this context, the relevant device parameters of the FETs such as saturation behaviour, field-effeet mobility, transconductance and sub-threshold slope will be analysed and compared. The chapter concludes with future perspectives for the fabrication of CNT-based FETs. 

Ambipolar mobility has also been reported from water soluble copper phthalo-cyanines substituted with sulfonic acid (45h) and methyl pyridinium groups (451). Unlike typical transistors with a linear and saturation regions, the drain-source current of these devices increases non-linearly with increasing V s at a given gate bias. Furthermore, the entire set of 1-V curves shifts up with repeated scans while the on/off ratio decreases. The authors attributed this behavior to a mechanism that involved ion-modulated electrical conduction. N-channel mobihties as high as 3 x... 

Figure 11.2. With the scanning tunnelling microscope, dispersed polyaniline (PAni) can be shown to consist of primary particles that are no larger than 10 nanometres (millionths of a millimetre). In (a) they can be seen as light, yellow-coloured patches. Once the volume concentration exceeds a critical threshold, these flocculate and—as can be seen in the scanning electron micrograph (b)—form network-like strucmres. Each of the particles behaves like a metal measuring a few nanometres, i.e. it possesses freely mobile electrons. These can tunnel between the particles and thereby conduct electricity. [Reproduced from ref. 17b with kind permission from Gordon and Breach publishers.]...

The ion mobility spectrum has many forms that share one common feature The ion current intensity is measured as a function of an ion s mobility in a gas. As with other types of spectrometry, the ion mobility spectrum is obtained by correlating a change in a spectrometer s parameter with a physical property of the ions. In light spectrometry, the number of photons is recorded as a function of photon energy in mass spectrometry, the number of ions is recorded as a function of mass, and in ion mobility spectrometry (MS), the number of ions is recorded as a function of an ion s collision cross section, which is related to its mobility. The type of IMS depends on the instrumental parameter that is scanned to produce the intensity versus mobility spectrum. To understand the many types of mobility spectra, we must first consider the relation among mobility, electric field, and pressure. 

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