2026-09-20T13:48:06Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/78357 2023-07-11 col_2142_5131 col_2142_8859 com_2142_5130 com_2142_8858 com_2142_234

Chang, Yia-Chung Stack, John D. Schleife, Andre Hubler, Alfred W. Ning, Zhenhua 2015-07-22T22:16:33Z 2015-07-22T22:16:33Z 2015-05 2015-04-13 The first principles study plays a very important role in developing new generation of materials, such as organic semiconductors and long polymer chains, as well as understanding of physical properties of nanoparticles , inorganic semiconductors and semiconductor alloys. In this work, we start from the Kohn-Sham one-particle equation Schr¨odinger equation and solve it by expanding its eigenfunctions in terms of the linear augmented-slater-type orbits(LASTO) under full potential with the exchange-correlation potential functional given by meta-generalized gradient approximation(mGGA). Our theoretical results were compared to WIEN2K’s, and good agreement was obtained. As the application, we apply TDDFT plus mGGA to calculate optical spectra for bulk solids. The result shows good agreement with experimental data. III-V ternary alloys AxB1−xC are promising materials for optoelectronic, high-speed electronic and microwave applications, such as infrared emitting diodes and detectors, high electron mobility transistors, heterojunction bipolar transistors, quantum-dot lasers, modulators and ultrafast switches. We adopted the TDDFT theory and the cluster averaging method to compute the spectra of III-V ternary alloys with arbitrary concentration x. We find great agreement between theoretical and experimental data. The success of this method is mainly because that we approximate the transition matrix elements by the LDA p-matrix elements via (mGGA) which contains the singularity of the type fXC,00(q) ∼ 1/q2 as q → 0. Thus, Our studies provide some insight into the theoretical calculation of optical spectra of semiconductor alloys. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2015-07-22 without embargo terms The student, Zhenhua Ning, accepted the attached license on 2015-04-09 at 16:54. The student, Zhenhua Ning, submitted this Dissertation for approval on 2015-04-09 at 17:09. This Dissertation was approved for publication on 2015-04-13 at 14:28. DSpace SAF Submission Ingestion Package generated from Vireo submission #7809 on 2015-07-22 at 10:31:33 Made available in DSpace on 2015-07-22T22:16:33Z (GMT). No. of bitstreams: 2 NING-DISSERTATION-2015.pdf: 8391224 bytes, checksum: 2777286977933c7d8c68380e07030130 (MD5) LICENSE.txt: 4209 bytes, checksum: 40776de8885a8172d13066b968b7c075 (MD5) Previous issue date: 2015-04-13 application/pdf http://hdl.handle.net/2142/78357 en Copyright 2015 Zhenhua Ning Time-dependent Density Functional Theory (TDDFT) 2015-5 semiconductor semiconductor alloys optical spectrum Linearized Augmented Slater-type Orbital (LASTO) meta-generalized gradient approximation (mGGA) Local Density Approximation (LDA) cluster averaging method Kohn-Sham exchange-correlation potential transition matrix element TDDFT calculations for excitation spectra of solids and superstructures utilizing mGGA text text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.