Papers by سهام ريف فالح الحربي
CiteSeer X (The Pennsylvania State University), 2009
The electrical conductivity (σ) and Hall coefficient (R H) of single crystals prepared by a speci... more The electrical conductivity (σ) and Hall coefficient (R H) of single crystals prepared by a special modified Bridgman technique have been investigated over the temperature range 245-495 K. Our investigation showed that our samples are p-type conducting. The dependence of the Hall mobility on temperature was presented graphically. The forbidden energy gap was calculated and found to be 2.1 eV whereas the ionization energy of the impurity level was 0.36 eV. The values of the electrical conductivity, Hall coefficient and carrier concentration at room temperature were 1.87 × 10-6 Ω-1 cm-1 , 3.98 × 10 9 cm 3 C-1 and 1.57 × 10 9 cm-3 respectively. The Hall mobility at room temperature (μ H) was found to be 7.46 × 10 3 cm 2 V-1 s-1. Also, the thermoelectric power (TEP) was investigated in the temperature range 271-493 K. The combination of the electrical and thermal measurements in the present investigation makes it possible to find various physical parameters such as mobilities, effective mass, relaxation times, diffusion coefficients and diffusion lengths both for majority and for minority carriers, Also figure of merit was determined. These parameters reveal the general behavior of this semiconductor.
Journal of King Abdulaziz University-science, 2008
High efficiency design for single crystal growth from melt based on Bridgman technique is constru... more High efficiency design for single crystal growth from melt based on Bridgman technique is constructed locally and used for growing TlInTe2 crystals. Measurements of Hall coefficient and DC electrical conductivity covering a temperature range from 158 to 473 K were conducted. The investigated samples have P-Type conductivity with RH of 2.3 × 109 cm3/coul. at room temperature and carrier concentrations as 2.81×109 cm-3. Energy gap ?Eg and ionization energy ?Ea were estimated as 0.72 eV and 0.113 eV, respectively. The diffusion coefficient, diffusion length, as well as relaxation time were evaluated, and the scattering mechanism of charge carrier was checked.
مجلة جامعة الملك عبدالعزيز, 2009
An Investigation was made of switching in TlGaSe 2 single crystals under static condition. Curren... more An Investigation was made of switching in TlGaSe 2 single crystals under static condition. Current-controlled negative resistance (CCNR) in TlGaSe 2 single crystals have been observed for the first time. It has been found that Thallium gallium diselenide single crystals exhibit bistable or memory switching. The results strongly indicated that the phenomenon in our sample is very sensitive to temperature, light intensity and sample thickness. The current-voltage characteristics is symmetrical with respect to the reverse of the applied voltage and current. The switching parameters were checked under the influence of different factors of the ambient condition.
High efficiency design for single crystal growth from melt based on Bridgman technique is constru... more High efficiency design for single crystal growth from melt based on Bridgman technique is constructed locally and used for growing TlInTe2 crystals. Measurements of Hall coefficient and DC electrical conductivity covering a temperature range from 158 to 473 K were conducted. The investigated samples have P-Type conductivity with RH of 2.3 × 109 cm3/coul. at room temperature and carrier concentrations as 2.81×109 cm-3. Energy gap ?Eg and ionization energy ?Ea were estimated as 0.72 eV and 0.113 eV, respectively. The diffusion coefficient, diffusion length, as well as relaxation time were evaluated, and the scattering mechanism of charge carrier was checked.
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Papers by سهام ريف فالح الحربي