Electronic properties of InP (001)/HfO2 (001) interface: Band offsets and oxygen dependence

Kc, Santosh; Dong, Hong; Longo, Roberto C.; Wang, Weichao; Xiong, Ka; Wallace, Robert M.; Cho, Kyeongjae

doi:10.1063/1.4861177

Cited by 16 publications

(15 citation statements)

References 42 publications

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“…The band offsets reported by Santosh et al . for a different O10 model (In terminated interfaces were not considered) seem to follow roughly this trend 22 . The band offsets are reflected also in the CLSs of the substitutional/impurity In and P atoms within deeper layers of the HfO 2 .…”

Section: Resultsmentioning

confidence: 70%

Unusual oxidation-induced core-level shifts at the HfO2/InP interface

Mäkelä

Lahti

Tuominen

et al. 2019

Sci Rep

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X-ray photoelectron spectroscopy (XPS) is one of the most used methods in a diverse field of materials science and engineering. The elemental core-level binding energies (BE) and core-level shifts (CLS) are determined and interpreted in the XPS. Oxidation is commonly considered to increase the BE of the core electrons of metal and semiconductor elements (i.e., positive BE shift due to O bonds), because valence electron charge density moves toward electronegative O atoms in the intuitive charge-transfer model. Here we demonstrate that this BE hypothesis is not generally valid by presenting XPS spectra and a consistent model of atomic processes occurring at HfO2/InP interface including negative In CLSs. It is shown theoretically for abrupt HfO2/InP model structures that there is no correlation between the In CLSs and the number of oxygen neighbors. However, the P CLSs can be estimated using the number of close O neighbors. First native oxide model interfaces for III-V semiconductors are introduced. The results obtained from ab initio calculations and synchrotron XPS measurements emphasize the importance of complementary analyses in various academic and industrial investigations where CLSs are at the heart of advancing knowledge.

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Section: Resultsmentioning

confidence: 70%

Unusual oxidation-induced core-level shifts at the HfO2/InP interface

Mäkelä

Lahti

Tuominen

et al. 2019

Sci Rep

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“… 66 Density functional theory studies have been interpreted in a similar light. 67 Our results suggest that, on the contrary, P-rich oxides may be beneficial for InP surface passivation.…”

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confidence: 65%

Effective Surface Passivation of InP Nanowires by Atomic-Layer-Deposited Al₂O₃ with PO_x Interlayer

et al. 2017

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III/V semiconductor nanostructures have significant potential in device applications, but effective surface passivation is critical due to their large surface-to-volume ratio. For InP such passivation has proven particularly difficult, with substantial depassivation generally observed following dielectric deposition on InP surfaces. We present a novel approach based on passivation with a phosphorus-rich interfacial oxide deposited using a low-temperature process, which is critical to avoid P-desorption. For this purpose we have chosen a POx layer deposited in a plasma-assisted atomic layer deposition (ALD) system at room temperature. Since POx is known to be hygroscopic and therefore unstable in atmosphere, we encapsulate this layer with a thin ALD Al2O3 capping layer to form a POx/Al2O3 stack. This passivation scheme is capable of improving the photoluminescence (PL) efficiency of our state-of-the-art wurtzite (WZ) InP nanowires by a factor of ∼20 at low excitation. If we apply the rate equation analysis advocated by some authors, we derive a PL internal quantum efficiency (IQE) of 75% for our passivated wires at high excitation. Our results indicate that it is more reliable to calculate the IQE as the ratio of the integrated PL intensity at room temperature to that at 10 K. By this means we derive an IQE of 27% for the passivated wires at high excitation (>10 kW cm–2), which constitutes an unprecedented level of performance for undoped InP nanowires. This conclusion is supported by time-resolved PL decay lifetimes, which are also shown to be significantly higher than previously reported for similar wires. The passivation scheme displays excellent long-term stability (>7 months) and is additionally shown to substantially improve the thermal stability of InP surfaces (>300 °C), significantly expanding the temperature window for device processing. Such effective surface passivation is a key enabling technology for InP nanowire devices such as nanolasers and solar cells.

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“…The total DFT energies are used instead of the Gibbs free energies for the calculations of the formation energies because the entropy contributions and enthalpy changes due to finite temperatures (300-600 K) are negligible for all of the structures considered, resulting in no significant changes in the relative formation energies. The following equation to correlate the chemical potential with oxygen partial pressure has been used: 42,43 where p and p O are the partial pressures at temperature T and at one atmosphere, respectively. The whole range of thermodynamically allowed O chemical potential is labeled in the lower x-axis (see Fig.…”

Section: Resultsmentioning

confidence: 99%

“…We used the gas phase O 2 molecule and SO 2 as reference states, similarly to the formulation explained in previous works. 42,43 The standard molar enthalpies (heat) of formation (D f H ) at 298.15 K for MoS 2 , MoO 2 , and MoO 3 are À235.1, À588.9, and À745.1 kJ/mol (À2.436, À6.1035, and À7.7224 eV), respectively. 44 Their relative stability can be predicted by comparing the heat of formation of these materials from their constituents.…”

Section: Resultsmentioning

confidence: 99%

Surface oxidation energetics and kinetics on MoS2 monolayer

Longo

Wallace

et al. 2015

Journal of Applied Physics

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168

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In this work, surface oxidation of monolayer MoS 2 (one of the representative semiconductors in transition-metal dichalcogenides) has been investigated using density functional theory method. Oxygen interaction with MoS 2 shows that, thermodynamically, the surface tends to be oxidized. However, the dissociative absorption of molecular oxygen on the MoS 2 surface is kinetically limited due to the large energy barrier at low temperature. This finding elucidates the air stability of MoS 2 surface in the atmosphere. Furthermore, the presence of defects significantly alters the surface stability and adsorption mechanisms. The electronic properties of the oxidized surface have been examined as a function of oxygen adsorption and coverage as well as substitutional impurities. Our results on energetics and kinetics of oxygen interaction with the MoS 2 monolayer are useful for the understanding of surface oxidation, air stability, and electronic properties of transition-metal dichalcogenides at the atomic scale. V

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Electronic properties of InP (001)/HfO2 (001) interface: Band offsets and oxygen dependence

Cited by 16 publications

References 42 publications

Unusual oxidation-induced core-level shifts at the HfO2/InP interface

Unusual oxidation-induced core-level shifts at the HfO2/InP interface

Effective Surface Passivation of InP Nanowires by Atomic-Layer-Deposited Al₂O₃ with PO_x Interlayer

Surface oxidation energetics and kinetics on MoS2 monolayer

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Electronic properties of InP (001)/HfO2 (001) interface: Band offsets and oxygen dependence

Cited by 16 publications

References 42 publications

Unusual oxidation-induced core-level shifts at the HfO2/InP interface

Unusual oxidation-induced core-level shifts at the HfO2/InP interface

Effective Surface Passivation of InP Nanowires by Atomic-Layer-Deposited Al2O3 with POx Interlayer

Surface oxidation energetics and kinetics on MoS2 monolayer

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Product

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Effective Surface Passivation of InP Nanowires by Atomic-Layer-Deposited Al₂O₃ with PO_x Interlayer