Electronic structure of Ge/Si self-assembled quantum dots with different shapes

Pyramid and hut shapes of self-assembled Ge quantum dots over a range of the lateral size of less than 500 إ and dome structures beyond the lateral size of 1000 إ are typically observed. We have investigated the electronic properties of approximate models of the pyramid and hut structures by taking the profiles of strain components into account. To obtain the elastic strain distribution, a valence force field model is used. The electronic confined state energies for electrons and holes are then obtained by diagonalizing the resultant Hamiltonian matrix of the Schrِdinger equation based on strain-modified potential. Theoretical results are compared with the transition energies observed by photoluminescence spectroscopy.