Optical properties of (AlAs)<i>n</i>(GaAs)<i>n</i> superlattices grown by metalorganic chemical vapor deposition

Ishibashi, Akira; Mori, Yusuke; Itabashi, Masao; Watanabe, Naozo

doi:10.1063/1.335905

Cited by 141 publications

(7 citation statements)

References 14 publications

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“…This VBO value is also at 34% of the directbandgap difference between AlAs and GaAs, in accordance with the photoluminescence data [36,40,41]. shown by the symbols •, , • and ∇ correspond respectively to the references [45], [46], [47] and [48]. As shown in this figure, the solid curve, corresponding to VBO = 0.56 eV, lies in between the other three theoretical curves and also is the least-squares fit to the scattered experimental data.…”

Section: Resultssupporting

confidence: 87%

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Ordering of conduction band states in thin-layer superlattices

Tit¹

1999

J. Phys.: Condens. Matter

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The electronic structures of thin-layer superlattices (SLs) are investigated versus the SL layer thicknesses (m, n) and the band offsets. The calculations are based on the empirical tight-binding model, which includes only nearest-neighbour interactions. Particular attention is given to the effect of the interface parametrization on the SL electronic properties. This is done, mainly, by varying the band offsets over a sufficiently broad range. The results show that the existence of type-II behaviour in the ultrathin-layer SLs necessitates a large valence band offset and small conduction band offset . Providing that these offset values are achieved, it is found that the highest state of the valence band is always confined to the GaAs slabs whereas the bottom state of the conduction band shows different behaviours as it is sensitive to band-mixing effects. It is due to these mixing effects that most of the ultrathin-layer SLs (with ) behave as type-II heterostructures, where the electrons are localized in the AlAs valley. The rest of the ultrathin-layer SLs behave as type-I heterostructures with a direct bandgap at the point, whenever the GaAs slabs are thick enough to make the electron confinement energy small in the GaAs wells. For thick-layer SLs, our results suggest the existence of a critical barrier thickness, beyond which the GaAs wells become completely decoupled and the SL behaves as a type I heterostructure. The estimated critical layer thickness, for the crossover from type-I to type-II behaviour, is for the SLs with m = n when using VBO = 0.56 eV. This -value is consistent with the photoreflectance experiments. The relevance of our work to photonic device applications is discussed further.

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Section: Resultssupporting

confidence: 87%

“…Figure 3. Comparison of the calculated energy gaps of the (AlAs) n (GaAs) n (001) superlattices with experiments: (•) reference[45]; ( ) reference[46]; (•) reference[47]; and (∇) reference[48]. The theoretical curves correspond to four different VBO values.…”

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confidence: 99%

Ordering of conduction band states in thin-layer superlattices

Tit¹

1999

J. Phys.: Condens. Matter

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“…In our previous work, we investigated the effects of modulation p-doping on the thermal stability of InAs/GaAs quantum dot superluminescent diodes, confirming that the improved thermal stability is related to the built-in holes in quantum dot structures [ 6 ]. It is noted that gallium arsenide (GaAs) and aluminum arsenide (AlAs) are perfectly lattice-matched, and few difficulties are expected in the growth of type-I (GaAs) m (AlAs) n semiconductor SLs, which consist of m monolayers of a GaAs well alternating with n monolayers of an AlAs barrier [ 7 , 8 ]. Many articles have been devoted to investigating the preparation, properties, and performances of (GaAs) m (AlAs) n SLs [ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

A High-Throughput Study of the Electronic Structure and Physical Properties of Short-Period (GaAs)m(AlAs)n (m, n ≤ 10) Superlattices Based on Density Functional Theory Calculations

Liu

Zhao

et al. 2018

Nanomaterials

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As important functional materials, the electronic structure and physical properties of (GaAs)m(AlAs)n superlattices (SLs) have been extensively studied. However, due to limitations of computational methods and computational resources, it is sometimes difficult to thoroughly understand how and why the modification of their structural parameters affects their electronic structure and physical properties. In this article, a high-throughput study based on density functional theory calculations has been carried out to obtain detailed information and to further provide the underlying intrinsic mechanisms. The band gap variations of (GaAs)m(AlAs)n superlattices have been systematically investigated and summarized. They are very consistent with the available reported experimental measurements. Furthermore, the direct-to-indirect-gap transition of (GaAs)m(AlAs)n superlattices has been predicted and explained. For certain thicknesses of the GaAs well (m), the band gap value of (GaAs)m(AlAs)n SLs exponentially increases (increasing n), while for certain thicknesses of the AlAs barrier (n), the band gap value of (GaAs)m(AlAs)n SLs exponentially decreases (increasing m). In both cases, the band gap values converge to certain values. Furthermore, owing to the energy eigenvalues at different k-points showing different variation trends, (GaAs)m(AlAs)n SLs transform from a Γ-Γ direct band gap to Γ-M indirect band gap when the AlAs barrier is thick enough. The intrinsic reason for these variations is that the contributions and positions of the electronic states of the GaAs well and the AlAs barrier change under altered thickness conditions. Moreover, we have found that the binding energy can be used as a detector to estimate the band gap value in the design of (GaAs)m(AlAs)n devices. Our findings are useful for the design of novel (GaAs)m(AlAs)n superlattices-based optoelectronic devices.

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“…For example high purity GaAs [1], GalnAs [2] and InP have been reported. OMVPE has recently achieved the distinction of producing extremely abrupt (_<5 A) interfaces in both the GaAs/AIGaAs [6] and InP/GalnAs [7] systems in reactors operating at atmospheric pressure. InP with 77 0 K mobilities exceeding 130,000 cm 2 Ns has been verified by many laboratories around the world [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Reactions in OMVPE Growth of InP

1987

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Organometallic vapor phase epitaxy (OMVPE) has achieved remarkable recent success, becoming the most promising technique for the ultimate production of IIIN materials and device structures. Unfortunately, our understanding of the growth process remains primitive. In this paper we report a new technique for tracing the reactions by conducting the epitaxial growth in a D 2 ambient using a time-of-flight mass spectrometer to analyze the product molecules. The pyrolysis reactions were studied for PH 3 , both alone and in the presence of trimethylindium (TMIn), and for TMIn alone and in the presence of PH 3 . For the reactants alone, the PH 3 pyrolysis is completely heterogeneous at the InP surface, while TMIn pyrolyzes homogeneously in the gas phase. For TMIn and PH 3 together, the reaction mechanism is entirely different; the pyrolysis temperatures for both PH 3 and TMIn are lowered. Since the reaction produces only CH 4 molecules, with a complete absence of CH 3 D at high ratios of PH 3 to TMIn, we hypothesize that InP growth is initiated by the direct interaction of TMIn and PH 3 molecules, either in the vapor phase at normal growth temperatures or at the InP surface at temperatures as low as 250 0 C.

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Optical properties of (AlAs)n(GaAs)n superlattices grown by metalorganic chemical vapor deposition

Cited by 141 publications

References 14 publications

Ordering of conduction band states in thin-layer superlattices

Ordering of conduction band states in thin-layer superlattices

A High-Throughput Study of the Electronic Structure and Physical Properties of Short-Period (GaAs)m(AlAs)n (m, n ≤ 10) Superlattices Based on Density Functional Theory Calculations

Reactions in OMVPE Growth of InP

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