Inhomogeneous semiconducting

Figure 6. The X-ray spectra firom 1.0 MeV proton bombardment of a) furnace black, b) mar resistant, and c) and d) two samples of the extra clean super smooth semiconductive compound. Note the improvement and the inhomogeneity of the remaining silicon and calcium.

Several methods of anodic (photoanodic in particular) etching have been suggested in the literature to reveal various inhomogeneities in the structure and composition of semiconducting crystals (see, e.g.. Refs. 104-106). 

Alternatively, chemical inhomogeneities and degradation have to be considered. It is well established, that local chemical impurities might act as electrically active trap states in a wide-band gap organic semiconducting host and reduce the effective mobility in the crystal [15, 49]. To judge on possible variation in the impurity concentration at the crystal surface and in the bulk it is necessary to carry out depth dependent chemical analyses, which we accomplished by repeated GC (see Section 25.2.2). 

Direct Local Measurements of Nanoscale Inhomogeneity of Conducting and Semiconducting Polymers... 

As far as can be seen from the available literature, the first locally resolved studies of nanoscale inhomogeneity of conducting and semiconducting polymers only appeared in... 

The development of scanning probe techniques, and in particular phase-imaging AFM, created a unique opportunity for researchers to directly study the local crystallinity and inhomogeneity of conducting and semiconducting 7t-conjugated polymers. Early... 

In addition to studies of nanoscale inhomogeneity of pristine semiconducting polymers, the NSOM technique and its variations were successfully used for imaging local nanoscale photocurrents and fluorescence emission produced by various polymer blends [119-124]. 

The spatial inhomogeneity of resistance in semiconducting cBN single crystals has thus far prevented detailed measurement of their electrical properties. The large and unstable contact resistances at the electrodes of cBN are also troublesome. Reported resistances of semiconduct-... 

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