Study on the Energy level Properties ofInGaAs/InGaAsP Self-Assembled Quantum Dots with Two Different Sizes
- We studied and characterized the energy levels of the InGaAs/InGaAsPquantum dot (QD) system with two differently sized layers byperforming capacitance-voltage and deep-level transient spectroscopy(DLTS) measurement. The sample has two QD layers stacked withdifferent sizes and a spacer layer of 100-nm in thickness. In theDLTS measurement for the QD sample with a 100 nm spacer, severalsignals were observed. The origins of two signals among them wereestimated to be a ground state and a high order confined energylevel in this QD system with two kinds of QDs. The highestactivation energy from small QDs was about 0.29 eV and this valuerepresented the location of the ground state energy level. A banddiagram of the double quantum dot system was suggested based on theDLTS measurements for various filling pulses and bias voltages.
- Keywords: Quantum dots, Energy level, InGaAs/InGaAsP/InP, Deep-level transient spectroscopy