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Register a new userPreparing pure thin films from poly vinyl chloride and studying the effect of the rotating velocity on the optical constants
تحضير أفلام رقيقة نقية من بولي فينيل كلورايد PVC و دراسة تأثير سرعة الدوران على الثوابت الضوئية
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ختام قنجراوي( باحث )
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قمنا في هذا البحث بتحضير أفلام رقيقة نقية من بوليمير فينيل كلورايد PVC, بطريقة التغطية بالدوران (Spin Coating), من أجل ثلاث سرعات (1000,2000,3000)RPM, و ذلك بترسيبها على قواعد زجاجية من النوع (Microscope cover glass) عند درجة حرارة الغرفة. درست الامتصاصية (Absorbance) و النفوذية (Transmittance) لهذه الأفلام في المنطقة المرئية و فوق البنفسجية (UV-VIS) للأشعة الضوئية. علاوة على ذلك قمنا بحساب معامل الامتصاص α(absorbance coefficient) و عمق النفاذ الضوئي للسطح δ(Skin Depth) و معامل الانكسار (Reflectance coefficient) no, و معامل العزل الكهربائي ε بجزأيه الحقيقي و التخيلي, و حسبنا أيضاً قيمة فجوة الطاقة Eg للانتقالات الالكترونية المباشرة المسموحة منها و الممنوعة. أظهرت الأفلام نفوذية عالية بحدود (80-90)% في مجال الأشعة تحت الحمراء و ذلك بدلالة سرعة الدوران فبلغت الحد الأقصى 80% تقريباً بالنسبة للسرعة 1000RPM, و 90% تقريباً بالنسبة للسرعة 3000RPM كما تناقصت قرينة الانكسار no بازدياد سرعة الدورانحيث وجدنا أنها تتراوح بين3.67 و 4.56 عند السرعتين 3000RPM و 1000RPM على الترتيب في حين تناقص عمق النفاذ السطحي δبازدياد سرعة الدوران فكانت أصغر قيمة له 0.0000531cm عند السرعة 3000RPM, و أكبر قيمة له cm0.00023 عند السرعة 1000RPM.
In this research we have prepared thin films from poly vinyl chloride (PVC) by spin coating technique in three velocities (1000,2000,3000)RPM on glass substrate (Micro scope cover glass), at room temperature. The absorbance A, and transmittance T for the films were studied in the visible and ultra-violet region (UV-VIS). In addition,we have calculated the absorbance coefficient α, skin depth δ, refractive index no, dielectric constant ε (the real part and the imaginary part), also we have calculated the energy band gap of allowed and forbidden direct transitions. The films showed high transmittance (80-90)%, in the infrared region as a function of the spinning velocity and took the maximum value 80% for the velocity 1000RPM, and 90% for the velocity 3000RPM, and the refractive index was decreased with the velocity increase, we found it between3.67 and 4.56 for the velocities 3000RPM and 1000RPM respectively. Whereas the skin depth δ decreased with the increasing of velocity, the minimum value was 0.0000531cm for the velocity 3000RPM and the maximum value was almost 0.00023cm for the velocity 1000RPM.
References used
AGUILAR R.G. et al, Low cost instrumentation for spin-coating deposition of thin films in an undergraduate laboratory. Latin American Journal of physical Education , Vol. 5, No.2, Mexico, 2011, 368-373
GRASSI A. G. et al ,On-line thickness measurement for two-layer system on polymer electric devices. Journal of Sensors, Munich, Germany, Vol. 13, 2013,47-57
ILICAN S. et al ,preparation and characterization of ZnO thin films deposited by sol-gel coating method. Journal of optoelectronic and advanced materials, Turkey, Vol. 10,2008, 2578-2583
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