This paper reviews the current status of minority carrier lifetime in n-type and p-type (Hg, Cd)Te. This review includes a discussion of the relevant (Hg, Cd)Te recombination mechanisms and measurement techniques. The reported experimentally determined lifetimes were related to (Hg, Cd)Te material iproperties of carrier concentration, Shockley-Read-Hall centres, non-uniformities ,and dislocation densities

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In this study, we employed Multiple Internal Reflection Infrared Spectroscopy (MIR-IR) to characterize chemical bonding structures of boron doped hydrogenated amorphous silicon (a-Si:H(B)). This technique has been shown to provide over a hundred fold increase of detection sensitivity when compared with conventional FTIR. Our MIR-IR analyses reveal an interesting counter-balance relationship between boron-doping and hydrogen-dilution growth parameters in PECVD-grown a-Si:H. Specifically, an increase in the hydrogen dilution ratio (H2/SiH4) was found to cause the increase in the Si-H bonding and a decrease in the B-H and SiH2 bonding, as evidenced by the changes in corresponding IR absorption peaks. In addition, although a higher boron dopant gas concentration was seen to increase the BH and SiH2 bonding, it also resulted in the decrease of the most stable SiH bonding configuration. The new chemical bonding information of a-Si:H thin film was correlated with the various boron doping mechanisms proposed by theoretical calculations.

A spatially resolved characterization technique is described that can separate surface and bulk (H~,Cd)Te material parameters. Photoconductive (PC) decay and metal-insulator semlc~nductor (MIS) measurements were used to characterize n-type (Hg,Cd)Te (x = 0.22) matenal and the anodic oxide-(Hg,Cd)Te interface. By analysis of the transient PC decay waveform, the surface recombination velocity and minority carrier lifetime were determined and then correlated to (Hg,Cd)Te material parameters. These results have been used to obtain estimates of the average bulk Shockley-Read density and surface state density.

In this work, we use contrast image processing to estimate the concentration of multi-wall carbon nanotubes (MWCNT) in a given network. The fractal dimension factor (D) of the CNT network that provides an estimate of its geometrical complexity, is determined and correlated to network resistance. Six fabricated devices with different CNT concentrations exhibit D factors ranging from 1.82 to 1.98. The lower D-factor was associated with the highly complex network with a large number of CNTs in it. The less complex network, having the lower density of CNTs had the highest D factor of approximately 2, which is the characteristic value for a two-dimensional network. The electrical resistance of the thin MWCNT network was found to scale with the areal mass density of MWCNTs by a power law, with a percolation exponent of 1.42 and a percolation threshold of 0.12 μg/cm2. The sheet resistance of the films with a high concentration of MWCNTs was about six orders of magnitude lower than that of less dense networks; an effect attributed to an increase in the number of CNT–CNT contacts, enabling more efficient electron transfer. The dependence of the resistance on the areal density of CNTs in the network and on CNT network complexity was analyzed to validate a two-dimension percolation behavior.