7 research outputs found
Gözenekli si ve ge nanoyapılarının ileri teknoloji güneş gözelerine uygulanması
TÜBİTAK MFAG01.04.2014Uluslararası ikili işbirliği projesi olan bu çalışmada amaca uygun olarak gözenekli silisyum ve germanyum nanoyapılar silisyum oksit matris içerisinde büyütülmüş ve optoleektronik aygıt üretiminde kullanılmıştır. Söz konusu yapıları elde edebilmek için silisyum ve germanyum-zengin silisyum oksit ince filmler fiziksel yolla buhar depolama yöntemlerinden yararlanarak üretilmiş ve kristal oluşumunu sağlamak için de yüksek sıcaklık fırını, hızlı termal tavlama ve lazer tavlama yöntemleri gibi farklı teknikler kullanılarak tavlanmıştır. Bu sayede farklı boyutlarda nanokristaller oluşturulmuş ve elde edilen yapıların optik band aralığının değişken olması sağlanmıştır. Böylece bu proje ile güneş spektrumundan daha fazla ve daha verimli yararlanmak amaçlı optik band aralığı ayarlanabilir malzemeler üretmiş bulunmaktayız. Öte yandan ürtetilen filmler, aygıt üretiminde gerekli olan elektrik akım geçişini sağlamk açısından da istenen şartları sağlamıştır. Böylece proejnin en önemli hedefi olan kuantum etkileri koruyarak, iletken tabakaların elde edilmesi hedefine ulaşılmıştır. Daha sonra bu yapılar, heteroeklem türü p-n eklemlei üretilmiş ve bu eklemlerin elektro- optik özellikleri belirlenmiştir. Si nanoyapılı örnekler güneş gözesi özellikleri sergilerken, Ge nanoyapılı örnekler de daha çok fotoalgılama yeteneği öne çıkmıştır. Bu çalışma ile ilk defa üretilen ve umut verici sonuçlar veren bu tür aygıtların daha da geliştirilmesi için yeni çalışmaların yürütülmesi gerekmektedir. Proje önerisi 24 ay gibi nispeten kısa bir sürede çok sayıda iş yapmayı hedefleyen bir proje olarak sunulmuştur. Uluslararası bir organizasonu da içeren zorlu bir programı olanproje hedeflerine büyük ölçüde ulaşmıştır. Çok sayıda deney ve çalışma yürütülmüştür. Bu çalışmaların bir özeti bu sonuç raporunda sunulmuştur.In this international bilateral cooperation project, silicon and germanium nanostructures embedded in silicon oxide matrix have been produced, optimized and used in some optoelectronic devices. In order to obtained these new material types, Si and Ge materials were co-sputtered together with SiO2 on a substrate, and annealed using conventional and rapid thermal annealing systems as well as laser annealing systems. In this way, nanostructures embedded in a dielectric matrix have been obtained. Such nanostructures are expected to yield materials with tunable band gap which depends on this size of the nanoparticles. A device having different band gap is expected to provide a more efficient light harvesting from the solar radiation. On the other hand, when these nanostructure are somehow interconnected, electrical transport becomes more feasible, which is contrary to the case where isolated nanocrystals are used. We have reached this goal through a series of experiments during this project. We have shown that both electrical transport and quantum confinement can be obtained in the same material system. After having optimized the material system, we have applied them to heterojunction type p-n diodes for demenstration. Devices with Si nanostructure have exhibited solar cell properties with weak efficiency, while those with Ge nanostructures have shown photodiode features only. These type of device have been produced for he first time in this project. They have shown some promising features. However, they need to be studied and optimized for an actual appliction. This porject was submitted as an ambitious study to be performed in a relatively short time. In addition to its scientific and tecjhnical program, it also included international oragnization tasks, which sometimes slows down the prject execution In spite of laa these difficulties, and the heavy content, we have achived most of goals through extensive experiments and studies. Below, we present a summary of our project acitivities and the results obtained from these studies
Graphene-quantum dot hybrid optoelectronics at visible wavelengths
With exceptional electronic and gate-tunable optical properties, graphene provides new possibilities for active nanophotonic devices. Requirements of very large carrier density modulation, however, limit the operation of graphene based optical devices in the visible spectrum. Here, we report a unique approach that avoids these limitations and implements graphene into optoelectronic devices working in the visible spectrum. The approach relies on controlling nonradiative energy transfer between colloidal quantum-dots and graphene through gate-voltage induced tuning of the charge density of graphene. We demonstrate a new class of large area optoelectronic devices including fluorescent display and voltage-controlled color-variable devices working in the visible spectrum. We anticipate that the presented technique could provide new practical routes for active control of light-matter interaction at the nanometer scale, which could find new implications ranging from display technologies to quantum optics.European Research Council (ERC) ERC 682723 SmartGraphene; TUBITAK (113F278
An interim analysis of the Turkish Myeloma Registry among patients who have received up to two lines of therapy
Background To investigate the demographics and treatment details of the myeloma patients who were diagnosed and followed up in Turkey and received up to two lines of therapy. Methods Patients who were recorded on the database of Turkish Myeloma Registry project were included in this study if they had only received one or two lines of therapy. Demographics, patient, and disease related parameters both at the time of diagnosis and at the follow up and treatment outcomes were presented
An interim analysis of the Turkish myeloma registry among the patients who have received up to two lines of therapy
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