İKİ AŞAMALI YÖNTEM İLE HAZIRLANAN Cu2ZnSnS4 (CZTS) İNCE FİLMLERİN ÖZELLİKLERİNDE SÜLFÜRLEMENİN ETKİSİ

Bu çalışmada CZTS ince filmler; Cu, Zn ve Sn metalik katmanların saçtırma yöntemi ile Cu/Sn/Zn/Cu yapılarının cam üzerine kaplanması ve bu yapıların 540 ve 580 °C sıcaklıkta 1 ve 5 dakika sürelerince sulfur atmosferinde sülfürlenmesi şeklinde iki-aşamalı metot kullanılarak büyütülmüştür. Değişik sıcaklık ve sürelerde sülfürlenen örnekler XRD, SEM, EDX, Raman spektroskopisi, Optik spektroskopi ve Van der Pauw yöntemleri kullanılarak karakterize edilmiştir. Tabakalı metalik yapı (Cu/Sn/Zn/Cu) ve CZTS örneklerinin Cu-zengini ve Zn-fakiri kompozisyona sahip olduğu gözlemlendi. Üretilen CZTS ince filmlerin XRD verileri incelediğinde, çok az Cu2-xS fazı dışında neredeyse saf CZTS yapısına sahip kırınım deseni gösterdiği görülmüştür. Raman spektroskopisi kullanılarak CZTS fazının oluştuğu teyit edilmiştir. SEM görüntüleri incelendiğinde, CZTS540-1 örneğinin daha kompakt, yoğun ve homojen bir yapıya sahip olduğu gözlemlenmiştir. Elde edilen optik yasak enerji aralıklarının literatür ile uyum içinde olduğu görülmüştür. Elektriksel ölçümler, CZTS540-1 ince filminin en yüksek taşıyıcı yoğunluğuna ve en düşük özdirenç değerlerine sahip olduğunu göstermiştir.

Anahtar Kelimeler:

CZTS, Saçtırma, Sülfürleme Süresi, Sülfürleme Sıcaklığı, Iki-aşamalı Metot

INFLUENCE OF SULFURIZATION ON THE PROPERTIES OF Cu2ZnSnS4 (CZTS) THIN FILMS PREPARED BY A TWO-STAGE PROCESS

In this study, CZTS thin films were grown by a two-stage method involved sputter deposition of metallic Cu, Zn, and Sn layers to form Cu/Sn/Zn/Cu metallic stacks on glass and sulfurization of the metallic stacks at 540 and 580 °C for 1 and 5 min in sulfur vapor atmosphere. The reacted samples at two different sulfurization temperatures and sulfurization times were characterized employing XRD, SEM, EDX, Raman spectroscopy, optical spectroscopy, and Van der Pauw methods. The metallic stacks and CZTS thin films showed Cu-rich and Zn-poor composition. XRD patterns of the reacted films showed almost pure kesterite CZTS phase except for presence of very small amount of Cu2-xS phase. Raman spectra of the films verified formation of kesterite phase in the films. SEM images showed that the CZTS540-1 sample had more compact, denser and uniform structure. Optical band gap values were found to be in good agreement with the literature. The CZTS540-1 thin film showed the highest carrier concentration and lowest resistivity values amongst the other samples.

Keywords:

CZTS, Sputtering, Sulfurization Time, Temperature, Two-stage Method,

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