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Polyerystalline CdTe İnce Filmlerin Optik Soğurma (Seri A)

Optical Absorption in Polyerystalline CdTe Thin Films (Series A)

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Abstract (2. Language): 
The spectral dependence of the absorption coefficients in vacuum deposited polycrystalline CdTe thin films on transparent glass substrate using envelope method is presented over incident photon energies ranging between 0.5-1.6 eV. The method required only a measurement of optical transmittance at normal incidence and is based on the evaluation of the spectral position and the contrast of the interference fringes over a wide range of the incident photon energies. Light absorption at lower photon energies (below bandgap) may be ascribed to the structural imperfections. In this spectral region hypothetical transmittance spectrum, in the case of non-zero absorption displayed a fairly good agreement with the experimental spectrum. As is typical in compound semiconductors, a disorder related exponential absorption (Urbach) tail was observed below the fundamental (mobility) gap. Optical bandgap of as-deposited layers was determined using Tauc equations as ~1.53 eV.
Abstract (Original Language): 
Saydam cam lam üzerine vakumda buharlaştırma tekniğiyle büyütülen çoklu kristal CdTe ince filmlerin soğurma katsayılarının 0.5-1.6eV foton enerji aralığındaki spektral dağılımı verilmektedir. Kullanılan metot sadece normal açı altında optiksel transmisyon ölçümünü gerekli kılar ve girişim saçaklarının spektral genişliklerinin ve spektral konumlarının incelenmesine dayanır. Foton enerjisinin düşük olduğu bölgede ışığın soğurumu yapısal kusurlardan dolayı olabilir. Optik band aralığının dışındaki bölgede teorik olarak hesaplanan transmisyon deneysel olarak elde edilen spektruma oldukça yakın olduğu saptandı. Bileşik yarı-iletkenlere özgü yasak enerji aralığının kenarında yapı düzensizliğiyle ilişkili üstel (Urbach) kuyruğu gözlendi. İşlenmemiş filmlerin optiksel band aralığı Tauc denklemleri kullanılarak ~1.53 eV olarak hesaplandı.
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