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Structural and bonding states of self-assembled AIN quantum dots
Author
Mirpuri Chandru Gobindram
Supervisor
Xu, Shuyan
Abstract
Quantum confinement in semiconductor quantum dots (QDs) can lead to an increase in the optical band gap size. This paves the development of novel microelectronic and optoelectronic devices. Group 111-nitride semiconductor QDs such as A1N have great potential for applications as templates for the growth of novel GaNl6HSic low dimensional nanostructures, which are used in blue lasers and light-emitting diodes (LED).
In this work, self-assembled and highly oriented ALN QDs is successfully grown on Si(1 l l) substrates. The technique used to grow the high quality QDs is a radio frequency (RF) magnetron sputtering plasma assisted CVD system. The morphology of the self-assembled AlN dots are examined by field emission scanning electron microscopy (SEM) and substantiated by atomic force microscopy (AFM). The results show highly consistent A1N dots uniformly distribute throughout the substrate. X-ray diffraction peaks reveal the formation of c-oriented (002) QDs and the size of the dots varies from -5-20 nm, depending on the growth conditions. The dot sizes agree remarkably well with measurements from SEM and AFM. The growth dynamics of the dots is found to obey cubic root-law behavior. Raman and Fourier transform infrared spectroscopy depict the characteristic AIN E2 (high) and E, (TO) phonon modes governing the AI-N bonding. X-ray photoelectron spectroscopy analysis suggests that the QDs feature a chemically pure and near stoichiometric AlN. AIN QDs grown by direct current (DC) magnetron sputtering revealed similar results.
The properties of A1N films, grown for longer duration, exhibit a zople I columnar stnicture of typical length -200-500 nm with an aspect ratio of about 12. The columnar structure is examined to be embedded in an amorphous layer of - few nm thick and singly oriented in the (002) direction. The bonding states of the AIN film are predominantly the E2 (high) and E, (TO) phonon modes.
In this work, self-assembled and highly oriented ALN QDs is successfully grown on Si(1 l l) substrates. The technique used to grow the high quality QDs is a radio frequency (RF) magnetron sputtering plasma assisted CVD system. The morphology of the self-assembled AlN dots are examined by field emission scanning electron microscopy (SEM) and substantiated by atomic force microscopy (AFM). The results show highly consistent A1N dots uniformly distribute throughout the substrate. X-ray diffraction peaks reveal the formation of c-oriented (002) QDs and the size of the dots varies from -5-20 nm, depending on the growth conditions. The dot sizes agree remarkably well with measurements from SEM and AFM. The growth dynamics of the dots is found to obey cubic root-law behavior. Raman and Fourier transform infrared spectroscopy depict the characteristic AIN E2 (high) and E, (TO) phonon modes governing the AI-N bonding. X-ray photoelectron spectroscopy analysis suggests that the QDs feature a chemically pure and near stoichiometric AlN. AIN QDs grown by direct current (DC) magnetron sputtering revealed similar results.
The properties of A1N films, grown for longer duration, exhibit a zople I columnar stnicture of typical length -200-500 nm with an aspect ratio of about 12. The columnar structure is examined to be embedded in an amorphous layer of - few nm thick and singly oriented in the (002) direction. The bonding states of the AIN film are predominantly the E2 (high) and E, (TO) phonon modes.
Date Issued
2003
Call Number
TK7874.88 Gob
Date Submitted
2003