Size Quantization and Zero Dimensional Effects in Self Assembled Semiconductor Quantum Dots

In this paper we discuss size quantization effects in InAs self assembled quantum dots deposited by molecular beam epitaxy (MBE) on (100) GaAs. The quantum dot size measurements are performed by transmission electron microscopy while the energy levels from the same samples are measured by capacitance, photoluminescence, photovoltage and electroluminescence techniques. Size quantization effects are observed, however variations in the quantum dot shapes, composition fluctuations and non uniform size distribution, which are deposition dependent prevent complete and accurate quantification of these effects. Through infrared absorption measurements together with capacitance measurements, the zero dimensional character of the quantum dots and “the atomic like” shell structure of the electronic levels in the quantum dots are established.