Yan, Fei
(2010)
LOW TEMPERATURE PHOTOLUMINESCENCE STUDY ON DEFECT CENTERS IN SILICON CARBIDE.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
This thesis reports the study of several intrinsic defect centers in SiC, mainly by optical characterization techniques. Different defect centers were created by either electron irradiation or ion implantation into n-type and p-type doped SiC following by annealing at different temperatures. Low temperature photoluminescence (LTPL) was used to study the optical properties of these defect centers. The no phonon lines from the dicarbon antisite defect center were observed with their phonon replicas. The stretch frequencies of the dicarbon dumbbell model are observed up to the fifth harmonic. The Morse Potential model was found to explain the anharmonicity quite well. First principles calculations were carried out by our collaborator Dr. A. Gali and show excellent agreement with the experiment and the Morse Potential results. It is clear that the dicarbon antisite defect is indeed responsible for the LTPL spectra. We also studied the evolution of the DI deep defect centers at different annealing stages and attempted to find correlations between the DI center in LTPL and the Z1/Z2 center at EC - 0.68 eV or the HS1 center at EV + 0.35 eV in deep level transient spectroscopy (DLTS). Our results indicate that in n-type 4H SiC there is no correlation between the Z1/Z2 center in DLTS and the L1 peak of the DI center seen in LTPL. In p-type 4H SiC we do not find a correlation between the HS1 DLTS peak and the LTPL L1 peak of the DI center. Consequently, we cannot find evidence for a 343 meV ground state postulated in the pseudodonor model.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
29 January 2010 |
| Date Type: |
Completion |
| Defense Date: |
4 December 2009 |
| Approval Date: |
29 January 2010 |
| Submission Date: |
5 August 2009 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Physics |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Low Temperature Photoluminescence; Silicon Carbide; Deep Defects |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-08052009-012630/, etd-08052009-012630 |
| Date Deposited: |
10 Nov 2011 19:57 |
| Last Modified: |
15 Nov 2016 13:48 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/8913 |
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