Non-linear effects of nanostructure silicon prep-arect by different technique

مقدم أطروحة جامعية

Muhammad, Salman Muhammad

مشرف أطروحة جامعية

Rashid, Bassam Ghalib

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة الليزر و الإلكترونيات البصرية

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2010

الملخص الإنجليزي

Silicon no's-tinctures have been synthesized by electrochemical, photocell Petrochemical and laser-induced etching techniques.

Various porous layers constituting; silicon nanostructures of different features were prepared due to silicon atoms detachment by the etching process.

We have extensively investigated the preparation dynamic of the n a no structured silicon during the etching process for the above-mentioned techniques.

This investigations based on the non-linear phenomenon which is called self-phase modulation.

In-situ monitoring, of the preparation dynamic could provide a valuable information about the progress of the nanostructured layer formation which makes the production mechanism real able and controllable.

It is found that the nanostructured layer generates an optical fringe patterns when the nanocrystailite size decreases less than (8 mm) due to the quantum confinement effect which enhances the non-linearity of the refractive index of the porous layer.

It is found that the minimum mean nanocrystailite size was CI-3 nm) which is obtained at 5 minutes irradiation time, 15 W/cm3 and 532 nm wavelength while optimum change in the refractive index was (0.49) at 7 minutes, IS WVcm2 and S10 nm wavelength.

Moreover, the maximum change in the reflectivity of the porous layer was (0.43) when laser wavelength of 645 nm, 10 W / cm3 and 5 minutes irradiation time.

Tike surface morphology investigations reveal that the nanostructured layer of various structures could be produced and that depends on the preparation parameters.

Moreover, gratings of sabmicjoiis scale can be made when proper processing parameters are selected precisely, The SEM statistics imply that high pore density of smaller average pore diameter of 3 Jim are obtained when the HF concentration diluted to 30 % while the number of pores and average pore diameter (pore density) decreases from (45) and (1.5 urn) to (16) and (4, 5 Udi) when, the silicon wafer resistivity increases from 0.015 to 4 £2.cnn, respectively.

التخصصات الرئيسية

الفيزياء

الموضوعات

• تكنولوجيا النانو
• السيليكون
• أشباه الموصلات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305344