Study of electronic and optical properties of quantum dots

Shape-dependent electronic and optical properties of quantum dots (QD’s) have been simulated using the particle in a box concept and solving 3D Schrodinger equation by employing Quantum Dot Lab Software. Effect of the shape of equal sized QDs on its optical properties like absorption and its dependency on the incident angle of light and temperature of surroundings is largely unexplored. Isovolumic calculations of energy states of GaAs and InP QDs were carried out for different geometrical shapes. Out of various shapes considered, those with cylindrical shape were found to possess high energy eigenstates whereas cuboid shape associated themselves with the lowest energy eigenstates. However, with an increase in their volume, the value of corresponding energy eigenstates decreased in consonance with the other findings. Optical absorption properties of these systems were also studied as a function of temperature and incident angle of polarization in ‘temperature sweeping’ mode and ‘angle sweeping’ mode, respectively. The percentage increase in absorption was found to be largest for InP cuboid-shaped QDs. And also independent of any change in the incident angle. Our findings are very significant in increasing the efficiency of solar cells and improving the performance of optoelectronic devices such as lasers and photodetectors.