Quantum dot terahertz emission - A study of the structures and growth conditions

Terahertz (THz) emission by difference frequency generation (DFG) technique has attracted vast interests recently. Quantum dot (QD) system is proposed to be the best candidate for THz emission by DFG technique due to its large optical nonlinearity. For efficient QD THz emission, the QD transition energies must lie within the THz range (0.4-41 meV). However, QD transition energies generally fall outside the critical energy difference, i.e. more than 41 meV. In this work, we investigated the effects of QD structures and growth conditions on the energy states. Consequently, we determined the required QD structures and growth conditions needed to obtain energy difference in the THz range.