Growth parameters of indium arsenide quantum dots using metal organic vapour phase epitaxy

Abstract

Metal-organic vapour phase epitaxy (MOVPE) is a versatile system that is capable of growing various materials especially the II-VI and III-V semiconductor materials. However, growth conditions for each individual system are different from the other and need to be individually calibrated. The work presented in this thesis is to calibrate and determine the growth parameters for the growth of indium arsenide (InAs) quantum dots on gallium arsenide (GaAs) substrates via Stranski-Krastanov self-assembled growth mode. The experiment was done in the cleanroom using a newly installed MOVPE system at Ibnu Sina Institute for Fundamental Science Studies, UTM. The effect of various growth parameters on the dot nucleation have been studied using atomic force microscopy (AFM) for structural information and photoluminescence (PL) for optical characterization. The growth parameters studied include growth rate, temperature, and V/III ratio. A total of 15 samples have been grown with five samples represent each selected parameter. The surface morphology of each samples for each parameter was observed using AFM. Graphs of dots height and width were plotted and the optimal growth parameters were obtained. The result shows that optimal parameters for the InAs quantum dots growth were temperature of 550 oC, V/III ratio of 10 and growth time of 4 seconds. Three more samples with optimal parameters were then grown for the PL and energy dispersive X-ray (EDX) characterization. The results show strong confinement quantum dots have been successfully grown in this experiment. The results of this study can be used for further improvement of the indium arsenide quantum dots growth.