Electrical carrier density

Solid solutions are very common among structurally related compounds. Just as metallic elements of similar structure and atomic properties form alloys, certain chemical compounds can be combined to produce derivative solid solutions, which may permit realization of properties not found in either of the precursors. The combinations of binary compounds with common anion or common cation element, such as the isovalent alloys of IV-VI, III-V, II-VI, or I-VII members, are of considerable scientific and technological interest as their solid-state properties (e.g., electric and optical such as type of conductivity, current carrier density, band gap) modulate regularly over a wide range through variations in composition. A general descriptive scheme for such alloys is as follows [41]. 

The Hall effect, an electric field perpendicular to both the impressed current flow and to the applied magnetic field, gives information about the mobility of the charge carriers as well as their sign. The Hall coefficient RH - Ey/JxHe is proportional to the reciprocal of the carrier density. The Hall coefficient is negative for electron charge carriers. 

TSC experiments are analyzed assuming the sample behaves ohmic, i.e., the contacts do not introdnce an inhomogeneity in the distribution of the electric field or carrier density and a nniform bulk density of carriers extends through the entire sample. Contact barriers are neglected. 

TSDC experiments are customarily analyzed assuming the sample behaves ohmic, i.e., the contacts do not introduce an inhomogeneous distfibution of the electric field or carrier density and a uniform bulk density of carriers extend through the entire sample. Experiments were carried out in such a way as to minimize injection effects. Contact configuration was typical for TSDC experiments. Because the currents through the sample are, in almost aU cases, extremely small, we have used a sensitive DC ammeter (model Ul-15, detection limit <10 A) with a hnear output signal. The simplest way to obtain a record of TSDC is an X-Y recorder that displays I(T) and the temperature. The equipment for the extraction of trap-spectroscopic information may be connected with devices for electronic data processing. The experimental errors in determination are less than 2%. 

Capture and emission processes at a deep center are usually studied by experiments that use either electrical bias or absorbed photons to disturb the free-carrier density. The subsequent thermally or optically induced trapping or emission of carriers is detected as a change in the current or capacitance of a given device, and one is able to deduce the trap parameters from a measurement of these changes. 

LP-CVD ZnO The variation of the electrical properties for a boron-doped LP-CVD ZnO film in dependence on its thickness d is presented in Fig. 6.15. The electrical properties are resistivity p, carrier density N, and mobility p. 

Figures 6.37 and 6.38 show the variation of electrical properties as a function of the dopant content of ZnO films. Figure 6.37 shows the case of AP-CVD ZnO F with fluorine as dopant (here, the fluorine atomic fraction is considered as dopant content). Figure 6.38 shows the case of LP-CVD ZnO B with boron as dopant (here, the B2H6/DEZ ratio is considered as dopant content). The electrical properties taken into consideration are the conductivity a, the resistivity p, the mobility //, and the free carrier density N.

The more rectangular the. //E-curve appears, the higher the FF is and the better charge carriers are collected within the device. Finally, the conversion efficiency is defined as the ratio between electrical power density delivered by the solar cell under standard illumination conditions and the power density of the incident light Pnght... 

Further, the model allows us to estimate electrical losses in the device. Figures 5.18c and d show the local variations in the energy levels and the carrier densities for the bulk heterojunction solar cell for different mobilities. In Fig. 5.18c, balanced mobilities for electrons and holes are assumed, while Fig. 5.18d describes the situation for the case where the electron mobility is higher than the hole mobility. In the latter case recombination is enhanced as seen from the carrier densities, and the performance of the device (Jsc) is significantly lowered. 

Here q is the electronic charge, e is the dielectric constant of semiconductor, and eo is the permittivity of free space. The carrier density of holes1 is denoted by p and the electric field by F. Mott showed that the diffusion component of the current is negligible and... 

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