Publication: Düşük boyutlu sistmelerin elektronik özellikleri: dış manyetik alan etkisinde Ga1-xAlx As/ GaAs silindirik kuantum telinde hidrojenik safsızlıklar ve eksitonların bağlanma enerjileri
Abstract
DÜŞÜK BOYUTLU SİSTEMLERİN ELEKTRONİK ÖZELLİK-LERİ: DIŞ MANYETİK ALAN ETKİSİNDE Ga1-xAlxAs/ GaAs SİLİNDİRİK KUANTUM TELİNDE HİDROJENİK SAFSIZLIK-LAR VE EKSİTONLARIN BAĞLANMA ENERJİLERİ Düşük boyutlu sistemlerde elektron gazının elektrik ve manyetik alan altındaki davranışları hem teorik hem de deneysel açıdan büyük ilgi görmüştür. Bugüne kadar yapılan çalışmaların sonuçları; çeşitli elektronik ve fotonik aletlerin yapılmasında uygulama alanı bularak, düşük boyutlu sistemlerde kuantizasyon etkilerinin beklendiği gibi önemli optik ve manyetik özelliklere yol açtığını göstermiştir. Bu çalışmada, teorik olarak GaAs/ AlxGa1-xAs kuantum silindirik kare kuyu ve ilk kez önerilen ters parabolik kuşatma potansiyelinden oluşan kuantum teli eksensel dış manyetik alan altında incelenmiştir. Hidrojenik vericinin (donor) tel ekseninde ve eksen dışında olduğu durumlar için taban durumu bağlanma enerjisi ve eksiton taban durumu bağlanma enerjisi etkin kütle tekniği ve varyasyonel yöntemler kullanılarak hesaplanmıştır. Yapılan hesaplamaların sonucu, kare kuyu ve ters parabolik potansiyelden oluşan silindirik kuantum telleri için karşılaştırılmıştır. İkincisinde bağlanma enerjisinin, belli manyetik alan ve tel yarıçapı değerlerinde kare kuyudan farklı olarak ani ve keskin bir şekilde arttığı gözlenmiştir. Bu değişim belirli manyetik alan ve tel yarıçaplarında elektron (ve boşluğun) bulunma olasılık grafiklerinin çizimiyle ayrıntılı olarak yorumlanmıştır.
ELECTRONIC PROPERTIES of LOW DIMENSIONAL SYSTEMS: THE HYDROGENIC IMPURITIES and EXCITONIC BINDING ENERGIES IN CYLINDRICAL Ga1-xAlxAs/ GaAs QUANTUM WIRES UNDER an EXTERNALLY APPLIED MAGNETIC FIELD The behaviors of electron gas in low dimensional systems under the electric and magnetic fields have been great interest in both experimental and theoretical aspects. The conclusions of the work done so far, finding an application field in doings of electronic and photonic instruments, have shown to lead to the important optical and magnetic properties as expected quantization effects in low dimensional systems. In this dissertation, the quantum wires being formed by GaAs/ AlxGa1-xAs quantum cylindrical square well and the first time proposed inverse parabolic confined potential have been investigated under the axial external magnetic field. The binding energy of ground state for the case of axial and off-axial of hydrogenic donor and for the case of exciton has been calculated using the effective mass technique and the variational methods. As a conclusion of calculations, it has been compared of the quantum wires being formed by the square well and the inverse parabolic potentials. It has been observed that the binding energy of the latter is increased abruptly at a certain magnetic field and wire radius unlike square well. This change has been discussed in details in plotting the graphs of existence probability of electrons (or holes) at the certain magnetic fields and wire radius.
ELECTRONIC PROPERTIES of LOW DIMENSIONAL SYSTEMS: THE HYDROGENIC IMPURITIES and EXCITONIC BINDING ENERGIES IN CYLINDRICAL Ga1-xAlxAs/ GaAs QUANTUM WIRES UNDER an EXTERNALLY APPLIED MAGNETIC FIELD The behaviors of electron gas in low dimensional systems under the electric and magnetic fields have been great interest in both experimental and theoretical aspects. The conclusions of the work done so far, finding an application field in doings of electronic and photonic instruments, have shown to lead to the important optical and magnetic properties as expected quantization effects in low dimensional systems. In this dissertation, the quantum wires being formed by GaAs/ AlxGa1-xAs quantum cylindrical square well and the first time proposed inverse parabolic confined potential have been investigated under the axial external magnetic field. The binding energy of ground state for the case of axial and off-axial of hydrogenic donor and for the case of exciton has been calculated using the effective mass technique and the variational methods. As a conclusion of calculations, it has been compared of the quantum wires being formed by the square well and the inverse parabolic potentials. It has been observed that the binding energy of the latter is increased abruptly at a certain magnetic field and wire radius unlike square well. This change has been discussed in details in plotting the graphs of existence probability of electrons (or holes) at the certain magnetic fields and wire radius.