Master's Thesis from the year 2011 in the subject Physics - Quantum Physics, Shahjalal University of Science and Technology (Department of Physics), course: Nanostructure Physics, language: English, abstract: This book contains a comprehensive account of application of WKB method to pure Physics of nanostructures containing single or symmetric double barrier V(x) in their band model in presence of longitudinal magnetic field applied along x direction. It concentrates on effects on transmission coefficient of single and symmetric double barriers by three dimensional electron gas (3DEG). Analytical expressions for longitudinal magnetic field dependent transmission coefficient of single and symmetric double barrier of general shape are obtained first. These general expressions are then used to obtain analytical expressions of longitudinal magnetic field dependent transmission coefficient of single and symmetric double barriers of many different shapes we encounter in studying nanostructure Physics. This is followed by thorough numerical investigation to bring out effects of longitudinal magnetic field on transmission coefficient of all these barriers. Comparisons with standard results where available showed excellent agreements. Results of numerical investigation have been explained completely. The book makes well documented, with thorough calculation and discussion, pure Physics of semiconductor nanostructures.