Measurement and Analysis of Structural, Electronics Properties of Wurtzite Indium Nitride using X-ray Diffraction, Extended X-ray Absorption Fine Structure and Photoluminescence
Date Issued
2015
Date
2015
Author(s)
Pranoto, Ferry Wiryo
Abstract
This master thesis is about studying crystal structure properties of wurtzite structure Indium Nitride using high resolution X-ray diffraction spectroscopy (HR-XRD), and In k-edge Extended X-ray Absorption Fine Structure (EXAFS). The result of HR-XRD does not suffice in resolution since lattice constant results from two different planes differ around 0.13%. We then apply mathematical model to correct the value of the measured lattice constant. The mathematical corrected result of our lattice constant a is ~ 3.53154 to 3.53204 Å, lattice constant c is ~ 5.70437 to 5.70565 Å. Our corrected HR-XRD measurement result has error bar under 10-8 Å. Lattice constant a and c of our samples show significant trend in which whenever the crystal is expanded in basal plane (elongate lattice constant a), the crystal structure will contract in its height (shown in shortened of lattice constant c) and vice versa. We then establish crystal model of wurtzite InN to fit the In k-edge of EXAFS data using the corrected HR-XRD lattice constants. Using combination data from both HR-XRD and EXAFS we could complete the structural measurement of wurtzite InN. We succeed in measuring 1st nearest neighbor (bonds length between In and N), 2nd nearest neighbor (In – In), with these parameters we could then derive wurtzite crystal structure c/a is 1.6152, and internal parameter u (b/c) is 0.3765. We successfully demonstrate the capability of EXAFS and HR-XRD to measure the internal parameter u with error around 10-3A. We notice that despite the lattice different around sample to sample, internal parameter u result shows stability indicating there exists a bonding force to keep the unit tetragonal cell intact by altering their bonding angle. Our study is continued with photoluminescence measurement of InN, with most sample has single peak at 0.68-0.7 eV that correspond to conduction band to acceptor transition.
Subjects
HR-XRD
wurtzite lattice constant a,c
bond length
internal parameter u
Type
thesis
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