Calculation of intrinsic carrier concentration in tellurium taking anisotropy into account

1976 ◽  
Vol 54 (9) ◽  
pp. 967-969 ◽  
Author(s):  
C. H. Champness

The intrinsic carrier concentration in tellurium is calculated at room temperature from measured values of electrical conductivity, Hall coefficient, and transverse magnetoresistance, taking anisotropy into account in a simple way. The model assumes one value of mobility parallel and another perpendicular to the c axis for both the electrons and holes.

2012 ◽  
Vol 36 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Mehnaz Sharmin ◽  
Shamima Choudhury ◽  
Nasrin Akhtar ◽  
Tahmina Begum

Electrical properties such as electrical resistivity, Hall coefficient, Hall mobility, carrier concentration of p-type GaAs samples were studied at room temperature (300 K). Resistivity was  found to be of the order of 5.6 × 10-3?-cm. The Hall coefficient (RH) was calculated to be 7.69 × 10-1cm3/C and Hall mobility (?H) was found to be 131cm2/V-s at room temperature from Hall effect   measurements. Carrier concentration was estimated to be 8.12 × 1018/cm3 and the Fermi level was calculated directly from carrier density data which was 0.33 eV. Photoconductivity measurements  were carried on by varying sample current, light intensity and temperature at constant chopping     frequency 45.60 Hz in all the cases mentioned above. It was observed that within the range of sample current 0.1 - 0.25mA photoconductivity remains almost constant at room temperature 300K and it was found to be varying non-linearly with light intensity within the range 37 - 12780 lux. Photoconductivity was observed to be increasing linearly with temperature between 308 and 428 K. Absorption coefficient (?) of the samples has been studied with variation of wavelength (300 -  2500 nm). The value of optical band gap energy was calculated between 1.34 and 1.41eV for the material from the graph of (?h?)2 plotted against photon energy. The value of lattice parameter (a) was found to be 5.651 by implying X-ray diffraction method (XRD).DOI: http://dx.doi.org/10.3329/jbas.v36i1.10926Journal of Bangladesh Academy of Sciences, Vol. 36, No. 1, 97-107, 2012 


2015 ◽  
Vol 1120-1121 ◽  
pp. 383-387
Author(s):  
Yu Xiang Hui ◽  
Nan An ◽  
Kai Chen ◽  
Xiao Jun Li ◽  
Wei Long Li ◽  
...  

Graphene is a two-dimensional material consisting of single atomic layers of graphite. Its quality is markedly different from conventional graphite and semiconductor material. In this paper, electrical conductivity and Hall Effect of the graphene were measured at room temperature by Var der Pauw method. An ohmic contact of the sample and the electrodes was constructed and tested before the measurement of Hall Effect. With the help of the Var der Pauw method, the Hall voltages of the samples were measured under the static magnetic field and different input currents. Sequentially, a series of Hall parameters of graphene were obtained. The results shown that the Hall coefficient RH is 7.00*10-7 m3/C; the carrier concentration n is 10.52*1024 m-3 that is fifteen orders of magnitude bigger than silicon; the Hall element production sensitivity KH is 6.87*102 m2/C and the carrier mobility was 1,882.54 cm2·V-1·s-1 which is much bigger than silicon. The measurement results in this paper can provide some reference for graphene’s research and application in related areas.


1964 ◽  
Vol 42 (3) ◽  
pp. 519-525 ◽  
Author(s):  
W. B. Pearson

The electrical conductivity and absolute thermoelectric power of AuSb2 and Cu2Sb have been measured between 2.5° and 300 °K. Room-temperature Hall coefficients were also determined. Iron impurity causes a giant diffusion thermoelectric power at low temperatures in the compound Cu2Sb, as it has previously been found to do in Cu, Ag, and Au.


2008 ◽  
Vol 368-372 ◽  
pp. 666-668 ◽  
Author(s):  
Min Ling Liu ◽  
Fu Qiang Huang ◽  
Li Dong Chen

A series of Cu1-xAlS2 (x = 0 ~ 0.08) bulk samples were synthesized by spark plasma sintering. The electrical and optical properties were investigated. P-type conductions for all samples were confirmed by both positive Seebeck coefficient and Hall coefficient. Bulk undoped CuAlS2 had a high conductivity of about 0.9 S/cm with a large band gap of 3.4 eV at room temperature. For vacancy-doped in Cu site, the carrier concentration was highly enhanced, reaching 1.7 × 1019 cm-3 for 8 mol% doped sample, and without decreasing the bang gap. The introduction of vacancies destroys the continuity of Cu-S network, which decreases the Hall mobility.


1968 ◽  
Vol 46 (10) ◽  
pp. 1199-1206 ◽  
Author(s):  
Eric H. van Tongerloo ◽  
John C. Woolley

Room-temperature free-carrier Faraday rotation measurements in the wavelength range 6–25 μ and Hall-coefficient measurements have been made on polycrystalline n-type samples of InAsxSb1−x alloys of carrier concentration ~1017/cm3. Using these data and a Kane equation for the conduction band, values of the bottom of the band effective mass m0* have been determined over the whole alloy range. The results are compared with similar data from magnetothermoelectric power measurements and also with previously calculated data. From the m0* results, values of the square of the matrix element P2 have been calculated as a function of x.


2018 ◽  
Vol 31 (3) ◽  
pp. 20
Author(s):  
Sarmad M. M. Ali ◽  
Alia A.A. Shehab ◽  
Samir A. Maki

In this study, the ZnTe thin films were deposited on a glass substrate at a thickness of 400nm using vacuum evaporation technique (2×10-5mbar) at RT. Electrical conductivity and Hall effect measurements have been investigated as a function of variation of the doping ratios (3,5,7%) of the Cu element on the thin ZnTe films. The temperature range of (25-200°C) is to record the electrical conductivity values. The results of the films have two types of transport mechanisms of free carriers with two values of activation energy (Ea1, Ea2), expect 3% Cu. The activation energy (Ea1) increased from 29meV to 157meV before and after doping (Cu at 5%) respectively. The results of Hall effect measurements of ZnTe , ZnTe:Cu films show that all films were (p-type), the carrier concentration (1.1×1020 m-3) , Hall mobility (0.464m2/V.s) for pure ZnTe film, increases the carrier concentration (6.3×1021m-3) Hall mobility (2m2/V.s) for doping (Cu at 3%) film, but  decreases by increasing Cu concentration.


1994 ◽  
Vol 359 ◽  
Author(s):  
Jun Chen ◽  
Haiyan Zhang ◽  
Baoqiong Chen ◽  
Shaoqi Peng ◽  
Ning Ke ◽  
...  

ABSTRACTWe report here the results of our study on the properties of iodine-doped C60 thin films by IR and optical absorption, X-ray diffraction, and electrical conductivity measurements. The results show that there is no apparent structural change in the iodine-doped samples at room temperature in comparison with that of the undoped films. However, in the electrical conductivity measurements, an increase of more that one order of magnitude in the room temperature conductivity has been observed in the iodine-doped samples. In addition, while the conductivity of the undoped films shows thermally activated temperature dependence, the conductivity of the iodine-doped films was found to be constant over a fairly wide temperature range (from 20°C to 70°C) exhibiting a metallic feature.


1998 ◽  
Vol 545 ◽  
Author(s):  
Ke-Feng Cai ◽  
Ce-Wen Nan ◽  
Xin-Min Min

AbstractB4C ceramics doped with various content of Si (0 to 2.03 at%) are prepared via hot pressing. The composition and microstructure of the ceramics are characterized by means of XRD and EPMA. Their electrical conductivity and Seebeck coefficient of the samples are measured from room temperature up to 1500K. The electrical conductivity increases with temperature, and more rapidly after 1300K; the Seebeck coefficient of the ceramics also increases with temperature and rises to a value of about 320μVK−1. The value of the figure of merit of Si-doped B4C rises to about 4 × 10−4K−1 at 1500K.


2002 ◽  
Vol 16 (20n22) ◽  
pp. 3171-3174
Author(s):  
F. F. BALAKIREV ◽  
J. B. BETTS ◽  
G. S. BOEBINGER ◽  
S. ONO ◽  
Y. ANDO ◽  
...  

We report low-temperature Hall coefficient in the normal state of the high-Tc superconductor Bi 2 Sr 2-x La x CuO 6+δ. The Hall coefficient was measured down to 0.5 K by suppressing superconductivity with a 60 T pulsed magnetic field. The carrier concentration was varied from overdoped to underdoped regimes by partially substituting Sr with La in a set of five samples. The observed saturation of the Hall coefficient at low temperatures suggests the ability to extract the carrier concentration of each sample. The most underdoped sample exhibits a diverging Hall coefficient at low temperatures, consistent with a depletion of carriers in the insulating ground state. The Hall number exhibits a sharp peak providing additional support for the existence of a phase boundary at the optimal doping.


Sign in / Sign up

Export Citation Format

Share Document