İki-Boyutlu Tek-tabaka Karbon Nitrürlerin Fononik Kararlılık Analizi

Bu çalışmada, tek tabakalı C6 N6 and C6 N8 karbon nitrürlerin dinamik kararlılıklarını ve elektronik özelliklerini inceledik. Literatürde bir çok kez çalışılmış olan düzlemsel C6 N8 yerine, bükülmüş tek-tabakalı C6 N8’in dinamik olarak kararlı olduğunu bulduk. Düzlemsel C6 N8, negatif optik fonon modlarına sahipken, yapıda uygun bir şekilde oluşturulan bükülme bu imajinerliklerin ortadan kalkmasını ve sistemin dinamik olarak kararlı olmasını sağlamaktadır. Literatürde, tek tabakalı C6 N6 ’nın düzlemsel formunun kararlı olduğu bulunmuştur. Bu çalışmada, C6 N6’daki bükülmenin, düzlem-dışı enine akustik modun (ZA) ve optik dalın yumuşak modunun kararlılıklarını bozduğunu ortaya çıkardık. Hem bükülmüş C6 N8 hem de düzlemsel C6 N6, görünür bölge icinde olan sırasıyla 1.82 eV ve 1.58 eV dogrudan bant aralığına sahiptir. Bizim sonuçlarımız, spektrumun görünür bölge aralığında çalışan optik cihazların üretiminde faydalı olabilir.

Phononic Stability Analysis of Two-Dimensional Carbon Nitride Monolayers

In this study we examined the dynamical stability and electronic properties of carbon nitrides monolayers as C6N6 and C6 N8. We found thatbuckled form of C6 N8 monolayer is dynamically stable instead of planar C6N8, which has been studied many times in literature. While planarC6N8 has negative optical phonon modes, properly created buckling in the structure can make these imaginarities disappear and make the system dynamically stable. In the literature, the planar form of C6N6 monolayer is predicted to be stable. In this work, we find out thatbuckling in the C6 N6 destabilizes the out-of-plane transverse acoustic mode (ZA) and the soft mode of the optical branch. Both buckled C6 N8 and planar C6 N6 have direct band gap of 1.82 eV and 1.58 eV, respectively, which fall in the visible region. Our outcomes may be usefulin fabricating optical devices that operate in the visible range of the spectrum.

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