Adsorption and desorption kinetics of Ga on GaN(0001): Application of Wolkenstein theory

Bruno, Giovanni; Losurdo, Maria; Kim, Tong-Ho; Brown, April S.

doi:10.1103/physrevb.82.075326

Cited by 10 publications

(9 citation statements)

References 23 publications

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“…There is a consensus, supported by both theoretical and experimental results [ 35 , 36 , 37 ], that it is better to perform the MBE growth of GaN under Ga-rich conditions to achieve a stable surface with minimal surface roughness. From a structural point of view, nucleation of GaN during MBE growth shows a novel behavior under excess-Ga deposition conditions.…”

Section: Gan Surfacesmentioning

confidence: 99%

“…Such studies are important for understanding the mechanisms dominating the growth processes and subsequently how they can be manipulated to achieve certain surface characteristics. The authors of reference [ 36 ] show that experimental results on Ga adsorption and desorption on Ga-polar GaN can be rationalized using the Wolkenstein theory for adsorption on semiconductors [ 44 ] in which the surface Fermi level and/or the surface charge plays a dominant role in adsorbate chemisorption. They also show that because of the fixed polarization charge existing at the GaN (0001) surface, Ga adsorption and desorption processes involve both neutral and charged Ga states (due to charge transfer between the polar Ga face GaN surface and the Ga adsorbate).…”

Section: Gan Surfacesmentioning

confidence: 99%

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Surface Preparation and Deposited Gate Oxides for Gallium Nitride Based Metal Oxide Semiconductor Devices

Long

McIntyre

2012

Materials

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The literature on polar Gallium Nitride (GaN) surfaces, surface treatments and gate dielectrics relevant to metal oxide semiconductor devices is reviewed. The significance of the GaN growth technique and growth parameters on the properties of GaN epilayers, the ability to modify GaN surface properties using in situ and ex situ processes and progress on the understanding and performance of GaN metal oxide semiconductor (MOS) devices are presented and discussed. Although a reasonably consistent picture is emerging from focused studies on issues covered in each of these topics, future research can achieve a better understanding of the critical oxide-semiconductor interface by probing the connections between these topics. The challenges in analyzing defect concentrations and energies in GaN MOS gate stacks are discussed. Promising gate dielectric deposition techniques such as atomic layer deposition, which is already accepted by the semiconductor industry for silicon CMOS device fabrication, coupled with more advanced physical and electrical characterization methods will likely accelerate the pace of learning required to develop future GaN-based MOS technology.

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Section: Gan Surfacesmentioning

confidence: 99%

Section: Gan Surfacesmentioning

confidence: 99%

Surface Preparation and Deposited Gate Oxides for Gallium Nitride Based Metal Oxide Semiconductor Devices

Long

McIntyre

2012

Materials

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“…Accordingly, those toxic gases cannot be desorbed immediately after adsorption, and the recovery time becomes very long at room temperature. Recently, the introduction of a negative charge could effectively modulate the adsorption strength of a gas molecule on the substrate [37][38][39]. In this regard, the adsorption energies of NH 3 , H 2 S, and SO 2 on the doped PG with a different negative charge were calculated, and the results are shown in Figure 9.…”

Section: Recovery Of Doped Pg After Sensing Toxic Gasesmentioning

confidence: 99%

Density Functional Theory Study of B, N, and Si Doped Penta-Graphene as the Potential Gas Sensors for NH3 Detection

et al. 2022

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Designing a high-performance gas sensor to efficiently detect the hazardous NH3 molecule is beneficial to air monitoring and pollution control. In this work, the first-principles calculations were employed to investigate the adsorption structures, electronic characteristics, and gas sensing properties of the pristine and B-, N-, P-, Al-, and Si-doped penta-graphene (PG) toward the NH3, H2S, and SO2 molecules. The results indicate that the pristine PG is insensitive to those toxic gases due to the weak adsorption strength and long adsorption distance. Nevertheless, the doping of B, N, Al, and Si (B and Al) results in the transition of NH3 (H2S and SO2) adsorption from physisorption to chemisorption, which is primarily ascribed to the large charge transfer and strong orbital hybridizations between gas molecules and doping atoms. In addition, NH3 adsorption leads to the remarkable variation of electrical conductivity for the B-, N-, and Si-doped PG, and the adsorption strength of NH3 on the B-, N-, and Si-doped PG is larger than that of H2S and SO2. Moreover, the chemically adsorbed NH3 molecule on the N-, B-, and Si-doped PG can be effectively desorbed by injecting electrons into the systems. Those results shed light on the potential application of PG-based nanosheets as reusable gas sensors for NH3 detection.

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“…The impinging constituents have to overcome an activation barrier in order to be adsorbed at the substrate surface. The adsorbed atoms can be bound weakly (neutral adsorbate) to the surface or strongly (binding energies in the range of several eV) due to electron transfer between adsorbate and surface [78] . In the case of Ga, weak adsorption on GaN(0001) is observed [78] , which suggests that the Ga adatoms are sufficiently mobile for subsequent diffusion.…”

Section: Size Effectsmentioning

confidence: 99%

“…The adsorbed atoms can be bound weakly (neutral adsorbate) to the surface or strongly (binding energies in the range of several eV) due to electron transfer between adsorbate and surface [78] . In the case of Ga, weak adsorption on GaN(0001) is observed [78] , which suggests that the Ga adatoms are sufficiently mobile for subsequent diffusion. For this, the atoms have to overcome an activation barrier which is due to the surrounding lattice potential.…”

Section: Size Effectsmentioning

confidence: 99%

Position-controlled selective area growth of Ga-polar GaN nanocolumns by molecular beam epitaxy

Urban¹

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Gallium nitride (GaN) is a binary compound semiconductor which belongs to the group III nitrides (III−N). GaN crystallizes typically in the wurtzite structure and has a direct band gap of 3.4 eV. Other members of the III nitrides are indium nitride (InN) and aluminum nitride (AlN), which likewise are of wurtzite crystal phase. The direct band gaps are 0.7 and 6.2 eV, respectively. The GaN-based ternary alloys In Ga 1− N and Al Ga 1− N theoretically allow to tailor the fundamental band gap from the near infrared (InN) to the far ultraviolet (AlN) parts of the electromagnetic spectrum. No other materials system offers this range of direct band gaps [1] . In fact, GaN-based optoelectronic devices are firmly established in everyday life: Solid-state lighting for illumination applications such as full color displays, automotive headlights and ambient lighting [2] utilize GaN-based light emitting diodes (LEDs). High definition optical data storage devices such as Blu-ray players which operate at a wavelength of 405 nm are based on InGaN laser diodes (LDs).The outstanding properties of the III nitrides in general [1,3] , the possibility to continuously tune the band gap, and especially the high melting temperature and the wide band gap of GaN and AlN, allow to envision a variety of GaN-based (high power) optoelectronic applications. These comprise for example photovoltaics, full visible spectrum LEDs, blue and green LDs for projectors (InGaN), and ultraviolet LDs for photolithography, chemical analysis, and medical, as well as environmental applications (AlGaN) [4,5] .Despite the overwhelming application versatility various problems have to be encountered and overcome to pave the way towards this bright future. One of them is related to the growth direction: The III nitrides are subject to polarization effects which cause internal electric fields. In conventional III−N devices, the growth surface is the polar -plane which is described by the Miller-Bravais indices 0001 . The growth direction perpendicular to this plane is 0001 . For this specific geometry, the built-in electric fields are aligned along the growth direction of the light emitting region, which is detrimental to the performance of these devices. A possibility to circumvent or at least reduce these fields is the growth on nonpolar or semipolar surfaces. The former 1100 -and 1120 -surfaces are perpendicular to the -plane. The latter are identified by { } with nonzero , , indices and 10 :

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Adsorption and desorption kinetics of Ga on GaN(0001): Application of Wolkenstein theory

Cited by 10 publications

References 23 publications

Surface Preparation and Deposited Gate Oxides for Gallium Nitride Based Metal Oxide Semiconductor Devices

Surface Preparation and Deposited Gate Oxides for Gallium Nitride Based Metal Oxide Semiconductor Devices

Density Functional Theory Study of B, N, and Si Doped Penta-Graphene as the Potential Gas Sensors for NH3 Detection

Position-controlled selective area growth of Ga-polar GaN nanocolumns by molecular beam epitaxy

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