Hall mobility temperature dependence

Fio. 3. Dependence on hydrogenation temperature of the free-electron concentration (a) and the electron Hall mobility (b) in phosphorus-implanted n-type silicon (Johnson et al., 1987c). 

Harrison found essentially the same results using single crystals and sintered samples. The slopes of the logarithms of the Hall constant and conductivity plotted against inverse absolute temperature were practically identical. The mobility varied in magnitude from sample to sample, but not in temperature dependence. Little time dependence of the conductivity was observed and none for the Hall coefficient. 

A deeper insight into the lateral electrical homogeneity of the films, the limiting mechanisms of the Hall mobility, and the thermal activation energies of shallow and deep defect levels can be gained by temperature-dependent Hall and deep level transient spectroscopy (DLTS) measurements [57,59,60]. To give an example, the temperature dependence of the Hall mobility and... 

Fig. 7.18. Temperature dependence of the Hall mobility (top) and of the carrier concentration (bottom) of undoped PLD ZnO thin films on a-plane sapphire grown at different oxygen partial pressures (see legends). Note the different temperature scales. The film grown at highest pressure shows an unusual metal-like temperature dependence of the carrier concentration for T < 90K. By H. von Wenckstern [59]...

FIGURE 1 Composition dependence of the resistivity, the carrier concentration and the Hall mobility at room temperature [4],... 

All the cuprates described till now are hole superconductors. The nature of holes has been subject of considerable discussion (Chakraverty et al. 1988 Rao et al. 19896 Sarma Rao 1989). There has been no experimental evidence for the presence of Cum type species in the doped cuprates. Instead, there is considerable evidence from electron and X-ray spectroscopies for the presence of hybridized oxygen holes which can be represented as O-. The detailed description of the holes in terms of the d and p characters has been investigated (Bianconi 1990). Essentially, the mobile holes in the cuprates are present in the in-plane n band which has 0-2p character. The concentration of holes (in all but the T1 cuprates) are easily determined by iodometry or Fen-Fem titrations (Rao el al. 1991a Shafer Penney 1990). Since the Hall coefficients are temperature dependent, the chemical titration method becomes invaluable. 

Fig. 7.13. Temperature dependence of the Hall mobility for n- and p-type a-Si H. The gas-phase doping levels range from 10" to 5 x 10" (LeComber, Jones and Spear 1977).

Equations 1-4 can easily be set up on a PC and used to simulate or fit temperature-dependent mobility data. In an n-type sample, the only undetermined parameter is the acceptor concentration Na, so usually Na is varied to give the best fit to the data. (For this fit, the approximate carrier concentration, nn = 1/Re, can be used when n is required in the various scattering formulas.) Then, the Hall factor r = can be calculated at... 

Hall effect measurements were used to investigate the electrical properties of the poly-Si films formed by the ALILE process. Due to the incorporated Al, the poly-Si films are always p-type. At room temperature, a hole concentration of 2.6 x 1018 run 3 and a hole mobility of 56.3 cm2 V 1 s 1 were determined [16]. Temperature dependent Hall measurements revealed both valence band conduction and defect band conduction (two-band conduction). For such highly doped material, the presence of a defect band conduction is expected. The Al concentration in the poly-Si films was measured by secondary ion mass spectroscopy (SIMS). An Al concentration of about 3 x 1019 cm 3 was found, which is about a factor of 10 larger than the... 

The temperature dependence of hall mobility p vertical to c-axis of each specimen is shown in fig.4. The p of each specimen decreased with increasing temperature over the... 

FIGURE 2.1.20 Upper panel the temperature dependences of the Hall mobility, (solid circles) and the effective mobility, extracted from the conventional FET equations — that is, from the longitudinal FET conductivity and the density of charges, n, field induced above the threshold (Equation 2.1.2) (open circles). Lower panel the temperature dependence of the ratio of the Hall carrier density, %, to the density n. (From Podzorov, V. et al., Phys. Rev. Lett., 95, 226601, 2005.)... 

The optical activation energy of boron is about 0.7 eV [3,23], in contrast to the thermal activation energy of 0.39 eV [22] calculated from the temperature dependence of the Hall mobility. This difference was discussed by Veinger et al [24]. They found, from Hall and ESR measurements, that the deeper level is an activator for the high-temperature luminescence but not seen in the ESR spectra and that the shallow level is a paramagnetic state. 

Surprisingly, we do not observe from out Q T) data, even for doping in the one-percent region, any indication of the formation of a donor band affecting the electronic transport. LeComber et al. (1977) have inferred the presence of a donor band in highly phosphorus-doped a-Si H from their Hall mobility data. We note, however, that the temperature dependence of the Hall mobility as shown in Fig. 17 can be understood according to Eq. (27) by the presence of potential fluctuations. A possible explanation why a donor band is not observed in transport could be that the donor states are hidden by the distribution of tail states. 

Pohl et al. (1975) have reported the dc electrical conductivity. Hall coefficient and Hall mobility versus temperature for the (M. SmS) phase. Goncharova et al. (1976) have reported for several (S.C. SmS) and (M. SmS) samples the resistivity and the Hall coefficient versus temperature. From their results they developed a model for the electronic transitions and discuss its temperature dependence. 

According to studies of the temperature dependence of the electrical conductivity and the Hall effect of n-type samples in system 3, a weak variation in these properties with tenq>era-ture has been established, which indicates degeneracy of the electron gas and ionization of impurities, Similar measurements on p-type samples in the same system showed that there is a reversal of the sign of the Hall coefficient (at about 500 K), and a high ratio of the electron mobility to the hole mobility (B = 60-80) [7],... 

Fig. 5.26. Temperature dependence of Hall mobility of several As-Te-I and As-Te-Ge alloys (after Saeger et al. (1972)) and for vitreous (ASjSeg). As2le3 (after Roilos (1971)). Curves 6, 7, 8 correspond to x = 0.5,1,3, respectively.

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