Structural, optical and photovoltaic effect of thermal evaporated tin selenide thin films

العناوين الأخرى

التأثير التركيبي، البصري و الفوتوفلتائي لأغشية سلينايد القصدير المرسبة بطريقة التبخير الحراري

مقدم أطروحة جامعية

Ramadan, Amir Abbas

مشرف أطروحة جامعية

Hasan, Bushra Abbas
Muhammad, Ghusun Hamid

أعضاء اللجنة

Hasan, Nahidah Bukhit
al-Haddad, Rad M. S.

الجامعة

جامعة بغداد

الكلية

كلية العلوم

القسم الأكاديمي

قسم الفيزياء

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

الملخص الإنجليزي

The alloys of SnxSe1-x were prepared by quenching technique with different Sn content (x=0.1, 0.5 and 0.7) .Thin films of these alloys were prepared using thermal evaporation technique under vacuum of 10-5 mbar on glass, n-Si and p-Si single crystals substrates with deposition rate (10- 15nm/min) at different thicknesses (100, 200 and 300 nm).

The X–ray diffraction measurements for bulk SnxSe1-x showed that all alloys have polycrystalline structures and the peaks for x=0.1 identical with SnSe2, while for x=0.5 and 0.7 were identical with the SnSe standard peaks .The diffraction patterns of SnxSe1-x thin film show that with low Sn content (x=0.1) samples have amorphous structure with thickness of 100 and 200 nm and convert to polycrystalline structure with increase thickness to 300 nm.

While samples with x=0.5 and 0.7 show polycrystalline structure and degree of crystallinity increase with increasing thickness.

AFM measurements show that the average grain size increases while the average surface roughness decreases with the increase of Sn content and thickness.

The optical measurements show that the SnxSe1-x films have direct and indirect energy gap Eg opt and decreases with the increase of Sn content and thickness, but the optical constants such as refractive index (n), extinction coefficient (k) and dielectric constant (εr, εi) have a regular increase with the increase of Sn content and thickness.

The D.C measurements declared two activation energy and hence two transport mechanism for SnxSe1-x with x=0.1 and 0.5 transport to one activation energy when Sn content increase to 0.7.

The values of activation energies decrease while the conductivity increases with the increase of Sn content and the thickness.

Hall effect measurements show that the SnxSe1-x thin films n-type for x=0.1 while convert to p-type semiconductors at x=0.5 and 0.7 for all thicknesses due to transformation from the hexagonal phase of SnSe2 to the orthorhombic phase of SnSe.

Concentration of charge carriers nH increases with Sn content and thickness, while the mobility μH showed opposite manner.

The measurements of C-V at reverse bias voltage for SnxSe1-x/p-Si and SnxSe1-x/n-Si heterojunctions at (10kHz) frequency show that the junction were abrupt type and the depletion width and built–in potential decreases with the increase of Sn content and thickness while the concentration of charge carriers Nb shows opposite manner.

The current–voltage characteristics of heterojunctions show that the forward current at dark condition varies approximately exponentially with applied voltage and the junctions are coinciding with recombination– tunneling model.

I-V characteristics under illumination showed that the heterojunctions prepared from SnxSe1-x on the basis of n-Si and p-Si have a good efficiency and the best value at x=0.5 with thickness 200 nm deposited on n-Si substrate and at x=0.5 with 100 nm deposited on p-Si substrate.

التخصصات الرئيسية

الفيزياء

الموضوعات

• الخواص الضوئية

عدد الصفحات

109

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-606865