Numerical simulation of coupling effect on electronic states in quantum wires

73.21.Hb Quantum wires, 2.60.Cb Numerical simulation; solution of equations,

Electronic and optical properties of Cd

We report a numerical simulation of the conduction and valence band edges of Cd1-xZnxS nanocrystallites using a one — dimensional potential model. Electron — hole pairs are assumed to be confined in nanospheres of finite barrier heights. Optical absorption measurements are used to fit the bandgap of the Cd1-xZnxS nanocrystal material. A theoretical analysis is also made to calculate the energy location of bound excitons and the oscillator strength of interband transitions as a function of zinc composition. The aim of the latter study is to investigate the optical behavior of Cd1-xZnxS nanocrystals. An attempt to explain all the results is presented

Current Tunnelling in MOS Devices with Al2O3/SiO2 Gate Dielectric

With the continued scaling of the SiO2 thickness below 2 nm in CMOS devices, a large direct-tunnelling current flow between the gate electrode and silicon substrate is greatly impacting device performance. Therefore, higher dielectric constant materials are desirable for reducing the gate leakage while maintaining transistor performance for very thin dielectric layers. Despite its not very high dielectric constant (∼10), Al2O3 has emerged as one of the most promising high-k candidates in terms of its chemical and thermal stability as its high-barrier offset. In this paper, a theoretical study of the physical and electrical properties of Al2O3 gate dielectric is reported including I(V) and C(V) characteristics. By using a stack of Al2O3/SiO2 with an appropriate equivalent oxide thickness of gate dielectric MOS, the gate leakage exhibits an important decrease. The effect of carrier trap parameters (depth and width) at the Al2O3/SiO2 interface is also discussed

Electronic and optical properties of Cd 1-x Zn xS nanocrystals

We report a numerical simulation of the conduction and valence band edges of Cd 1-x Zn xS nanocrystallites using a one — dimensional potential model. Electron — hole pairs are assumed to be confined in nanospheres of finite barrier heights. Optical absorption measurements are used to fit the bandgap of the Cd 1-x Zn xS nanocrystal material. A theoretical analysis is also made to calculate the energy location of bound excitons and the oscillator strength of interband transitions as a function of zinc composition. The aim of the latter study is to investigate the optical behavior of Cd 1-x Zn xS nanocrystals. An attempt to explain all the results is presented. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 200673.21.La Quantum dots, 73.22.-f Electronic structure of nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals, 71.55.Gs II-VI semiconductors,