Structural and electrical characterization of InN, InGaN, and p-InGaN grown by metal-modulated epitaxy

Moseley, Michael William; Lowder, J.E.; Doolittle, W. Alan; Namkoong, Gon

doi:10.1116/1.4790865

Cited by 16 publications

(5 citation statements)

References 46 publications

(35 reference statements)

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“…The nitrogen plasma resulted in a beam equivalent pressure of ∼2.2 × 10 –5 Torr. The MME technique, as described in detail in previous works by this research group, was employed for the growth of each GaN film reported here. , RHEED was used for surface level in situ monitoring of the homoepitaxial GaN films during growth. A Philips X’Pert Pro MRD was used for post-growth XRD of the grown films.…”

Section: Methodsmentioning

confidence: 99%

Comprehensive Analysis of Metal Modulated Epitaxial GaN

Ahmad

Motoki

Clinton

et al. 2020

ACS Appl. Mater. Interfaces

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While metal modulated epitaxy (MME) has been shown useful for hyperdoping, where hole concentrations 40 times higher than other techniques have been demonstrated, and the ability to control phase separation in immiscible III-nitrides, the complexity of the dynamically changing surface conditions during the cyclic growth is poorly understood. While MME is capable of superb crystal quality, performing MME in an improper growth regime can result in defective material. These complications have made the transfer of MME knowledge challenging. This work provides a comprehensive study of the conditions necessary for achieving the benefits of MME while avoiding undesirable defects. The effects of growth temperature, Ga/N ratio, and excess Ga dose per MME growth cycle on the morphological, structural, electronic, and optical properties of unintentionally doped (UID) MME grown gallium nitride (GaN) have been investigated. Optimal structural and electrical quality were achieved for GaN films grown at ∼650 °C, at pre-bilayer Ga coverage and at the moderate droplet regime. However, high defect concentrations were observed at the lowest growth temperatures, and counter to traditional MBE, as the excess Ga dose transitioned from bilayer coverage to the low droplet regime. Optoelectronic properties were optimal for films grown at intermediate growth temperatures, an excess Ga dose condition just before the droplet formation, and, at a III/V ratio of 1.3. Optimization of growth temperatures, Ga/N ratios, and excess Ga dose results in a range of growth conditions achieving smooth surfaces, step-flow surface morphology, and high crystalline quality films with low threading dislocation densities, allowing researchers to utilize the extensive advantages of MME.

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Section: Methodsmentioning

confidence: 99%

Comprehensive Analysis of Metal Modulated Epitaxial GaN

Ahmad

Motoki

Clinton

et al. 2020

ACS Appl. Mater. Interfaces

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“…Desorption of InN is critical at raised temperatures because indium will evaporate from the sample surface. To retain indium in the nanorods, the metal-modulated epitaxy (MME) technique was utilized [67,68]. MME involves periodic opening and closing of the metal shutters in order to modulate the metal fluxes, while the N 2 shutter is kept open.…”

Section: Growth Techniquementioning

confidence: 99%

Light Trapping Induced High Short-Circuit Current Density in III-Nitride Nanorods/Si (111) Heterojunction Solar Cells

et al. 2020

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An effective-area photovoltaic efficiency of 1.27% in power conversion, excluding the grid metal contact area and under 1 sun, AM 1.5G conditions, has been obtained for the p-GaN/i-InGaN/n-GaN diode arrays epitaxially grown on (111)-Si. The short-circuit current density is 14.96 mA/cm 2 and the open-circuit voltage is 0.28 V. Enhanced light trapping acquired via multiple reflections within the strain and defect free III-nitride nanorod array structures and the short-wavelength responses boosted by the wide bandgap III-nitride constituents are believed to contribute to the observed enhancements in device performance.

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“…23,24 However, many research groups reported that the formation of highly crystalline InN NWs is difficult, notably because of the segregation phenomenon and easy desorption of In atoms from the NW surface. [25][26][27] As a result, self-powered TFSs fabricated with semiconductor III-nitride NWs have not been reported yet.…”

Section: Introductionmentioning

confidence: 99%