Document Details

Document Type : Thesis 
Document Title :
Growth and characterization of hexaindium heptaselenide and hexaindium heptasulfide semiconductor compounds
الإنماء البلوري والملامح المميزة لمركبات أشباه الموصلات سداسي الإنديوم سباعي السيلينيوم وسداسي الإنديوم سباعي الكبريت
 
Document Language : Arabic 
Abstract : In the past three decades , significant interest in chalcogenides compounds has been shown by various workers because of their interesting physical properties as well as their wide technological applications. Research on binary semiconducting compounds formed by elements from groups ( ) and ( ) of the periodic table as a collective group of materials have been and are still the subject of much intensive investigation . Number of semiconductor compounds from the groups have been the subject of intensive investigation in recent years as materials having promising properties . So they call the attention of many physicists to explore more and more of their hidden secrets , Among of these materials In6S7 and In6Se7 have been devoted a particular attention . Single crystal of In6S7 and In6Se7 were grown in the crystal growth laboratory ,using a special design for crystal growth from melt based on Bridgman technique . The product ingots were identified with x-ray analysis . The study of the Hall effect , electrical conductivity and thermoelectric power as well as switching effect .The investigated samples were p-type conducting for both In6S7 and In6Se7 , the Hall coefficient yields at room temperature concentration of 7.38x1013 cm-3 and 4.077x1012 cm-3 for In6S7 and In6Se7 respectively . The band gap was found to be for In6S7 ∆Eg=0.72 eV while for In6Se7 ∆Eg=0.8 eV. The ionization energy ΔEa were estimated as 0.11 eV and 0.72 eV for In6S7 and In6Se7 respectively . Hall coefficient RH for In6S7 was 8.47x104cm3/coul and for In6Se7 at 300⁰ k equal to 1.533x106 cm3/coul. Hence , a combination of the electrical conductivity and Hall effect measurements enable us to study the influence of temperature on the Hall mobility and to discuss the scattering mechanism of the charge carriers for In6S7 and In6Se7 . Also the present investigation involves thermoelectric power measure-ments of In6S7 and In6Se7 single crystals, These measurements enables us for the determination of many physical parameters such as carriers mobilities , effective masses of free charge carriers, diffusion coefficients and diffusion lengths , relaxation time of electrons and holes , as well as the figure of merit . The switching phenomena of our In6S7 and In6Se7 monocrystals was studied . Current – controlled negative resistance (CCNR) in both In6S7 and In6Se7 single crystal have been observed for the frist time .It has been found that In6S7 and In6Se7 exhibits memory switching . The results strongly indicated that the phenomenon in our samples 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 for both In6S7 and In6Se7 . The switching parameters of In6S7 and In6Se7 were checked under the influence of different factors of the ambient conditions . This mode of investigation (crystal growth and transport properties as well as switching phenomenon) is the ideal way for finding out the possibility of making application for these compounds , especially in the field of energy conversion , devices and electronic engineering 
Supervisor : Nagat Tawfeek Abbas 
Thesis Type : Doctorate Thesis 
Publishing Year : 1433 AH
2012 AD 
Number Of Pages : 305 
Added Date : Sunday, March 2, 2014 

Researchers

Researcher Name (Arabic)Researcher Name (English)Researcher TypeDr GradeEmail
جازي عبدالله عبدالواحدAbdulwahed, Jazi AbdullahInvestigatorDoctorate 

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