| 1. |
- Fülöp, Attila, 1988, et al.
(författare)
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Phase transition of bismuth telluride thin films grown by MBE
- 2014
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Ingår i: Applied Physics Express. - 1882-0786 .- 1882-0778. ; 7:4, s. Art. no. 045503-
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Tidskriftsartikel (refereegranskat)abstract
- A previously unreported phase transition between Bi2Te3 and Bi4Te3 in bismuth telluride grown by molecular beam epitaxy is recorded via XRD, AFM, and SIMS observations. This transition is found to be related to the Te/Bi beam equivalent pressure (BEP) ratio. BEP ratios below 17 favor the formation of Bi4Te3 while Bi2Te3 is formed at higher ratios. Transport measurements reveal that Bi2Te3 has higher electron mobility than Bi4Te3.
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| 2. |
- Segercrantz, N., et al.
(författare)
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Defect studies in MBE grown GaSb1-x Bi x layers
- 2014
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Ingår i: AIP Conference Proceedings. - : AIP Publishing LLC. - 1551-7616 .- 0094-243X. ; 1583, s. 174-177
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Konferensbidrag (refereegranskat)abstract
- Positron annihilation spectroscopy in Doppler broadening mode is used to study epitaxial layers of GaSb 1-x Bi x on undoped GaSb. The samples were grown by Molecular Beam Epitaxy at different temperatures and with different Bi/Sb beam equivalent pressure ratios resulting in Bi concentrations of 0-0.7 %. The results show a relationship between the growth parameters and Doppler broadening parameters. Incorporating Bi into GaSb decreases the vacancy concentration in the epitaxial layers compared to the sample with no Bi in the epitaxial layer.
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| 3. |
- Segercrantz, N., et al.
(författare)
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Point defect balance in epitaxial GaSb
- 2014
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 105:8, s. art. no. 082113-
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Tidskriftsartikel (refereegranskat)abstract
- Positron annihilation spectroscopy in both conventional and coincidence Doppler broadening mode is used for studying the effect of growth conditions on the point defect balance in GaSb:Bi epitaxial layers grown by molecular beam epitaxy. Positron annihilation characteristics in GaSb are also calculated using density functional theory and compared to experimental results. We conclude that while the main positron trapping defect in bulk samples is the Ga antisite, the Ga vacancy is the most prominent trap in the samples grown by molecular beam epitaxy. The results suggest that the p–type conductivity is caused by different defects in GaSb grown with different methods.
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| 4. |
- Zhao Ternehäll, Huan, 1982, et al.
(författare)
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Effect of buffer design on structural and electrical properties of InAs films grown on GaAs substrates
- 2014
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Ingår i: the 41st international symposium on compound semiconductors, Montepillier, France.
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Konferensbidrag (refereegranskat)abstract
- Different buffer structures were grown by molecular beam epitaxy (MBE) to accommodate the large lattice mismatch of InAs with GaAs substrate. A novel graded digital superlattice (GDSL) buffer design was proposed and compared with the common one-step buffer and linear alloy graded (LAG) buffer designs. Effect of buffer structures on structural and electrical properties of the InAs films was investigated. High quality InAs films were obtained on GaAs substrates.
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