Study of Edge and Screw Dislocation Density in GaN/Al2O3 Heterostructure

Ene, Vladimir Lucian; Dinescu, Doru; Zai, Iulia; Djourelov, Nikolay; Vasile, Bogdan Stefan; Serban, Andreea Bianca; Leca, Victor; Andronescu, Ecaterina

doi:10.3390/ma12244205

Open AccessArticle

Study of Edge and Screw Dislocation Density in GaN/Al₂O₃ Heterostructure

by

Vladimir Lucian Ene

^1,2

,

Doru Dinescu

^2,3,

Iulia Zai

^2,4,

Nikolay Djourelov

²

,

Bogdan Stefan Vasile

^1,*

,

Andreea Bianca Serban

^2,3,

Victor Leca

² and

Ecaterina Andronescu

¹

Department of Science and Engineering of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 060042 Bucharest, Romania

²

Extreme Light Infrastructure-Nuclear Physics (ELI-NP), ‘Horia Hulubei’ National R&D Institute for Physics and Nuclear Engineering (IFIN-HH), 30 Reactorului Street, 077125 Măgurele, Ilfov, Romania

³

Doctoral School in Engineering and Applications of Lasers and Accelerators, University Politehnica of Bucharest, 060042 Bucharest, Romania

⁴

Faculty of Physics, University of Bucharest, 077125 Măgurele, Ilfov, Romania

^*

Author to whom correspondence should be addressed.

Materials 2019, 12(24), 4205; https://doi.org/10.3390/ma12244205

Submission received: 11 November 2019 / Revised: 11 December 2019 / Accepted: 12 December 2019 / Published: 14 December 2019

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Abstract

This study assesses the characteristics (edge and screw dislocation density) of a commercially available GaN/AlN/Al₂O₃ wafer. The heterostructure was evaluated by means of high-resolution X-ray diffraction (HR-XRD), high-resolution transmission electron microscopy (HR-TEM), and Doppler-Broadening Spectroscopy (DBS). The results were mathematically modeled to extract defect densities and defect correlation lengths in the GaN film. The structure of the GaN film, AlN buffer, Al₂O₃ substrate and their growth relationships were determined through HR-TEM. DBS studies were used to determine the effective positron diffusion length of the GaN film. Within the epitaxial layers, defined by a [GaN

P 63 m c

(0 0 0 2) ||

P 63 m c

AlN (0 0 0 2) || (0 0 0 2)

R \bar{3} c

Al₂O₃] relationship, regarding the GaN film, a strong correlation between defect densities, defect correlation lengths, and positron diffusion length was assessed. The defect densities

ρ_{d}^{e} =

6.13 × 10¹⁰ cm⁻²,

ρ_{d}^{s} =

1.36 × 10¹⁰ cm⁻², along with the defect correlation lengths L^e = 155 nm and L^s = 229 nm found in the 289 nm layer of GaN, account for the effective positron diffusion length L_eff~60 nm.

Keywords: gallium nitride; epitaxial thin films; defect density; edge/screw defect; slow positrons

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MDPI and ACS Style

Ene, V.L.; Dinescu, D.; Zai, I.; Djourelov, N.; Vasile, B.S.; Serban, A.B.; Leca, V.; Andronescu, E. Study of Edge and Screw Dislocation Density in GaN/Al₂O₃ Heterostructure. Materials 2019, 12, 4205. https://doi.org/10.3390/ma12244205

AMA Style

Ene VL, Dinescu D, Zai I, Djourelov N, Vasile BS, Serban AB, Leca V, Andronescu E. Study of Edge and Screw Dislocation Density in GaN/Al₂O₃ Heterostructure. Materials. 2019; 12(24):4205. https://doi.org/10.3390/ma12244205

Chicago/Turabian Style

Ene, Vladimir Lucian, Doru Dinescu, Iulia Zai, Nikolay Djourelov, Bogdan Stefan Vasile, Andreea Bianca Serban, Victor Leca, and Ecaterina Andronescu. 2019. "Study of Edge and Screw Dislocation Density in GaN/Al₂O₃ Heterostructure" Materials 12, no. 24: 4205. https://doi.org/10.3390/ma12244205

APA Style

Ene, V. L., Dinescu, D., Zai, I., Djourelov, N., Vasile, B. S., Serban, A. B., Leca, V., & Andronescu, E. (2019). Study of Edge and Screw Dislocation Density in GaN/Al₂O₃ Heterostructure. Materials, 12(24), 4205. https://doi.org/10.3390/ma12244205

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Study of Edge and Screw Dislocation Density in GaN/Al₂O₃ Heterostructure

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