Plasma-assisted molecular beam epitaxy growth of high-density nitrogen-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and nitrogen radicals

We demonstrated plasma-assisted molecular beam epitaxy (MBE) growth of high-density nitrogen (N)-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and N radicals. The N density was controlled in a wide range of 1017–1021 cm−3, and single-crystal Ga2O3 thin films wit...

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Main Authors: Kura Nakaoka, Shoki Taniguchi, Tomoki Uehara, Jin Inajima, Kohki Tsujimoto, Yusuke Teramura, Satoko Honda, YongGu Shim, Masataka Higashiwaki
Format: Article
Language:English
Published: AIP Publishing LLC 2025-05-01
Series:APL Materials
Online Access:http://dx.doi.org/10.1063/5.0258551
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author Kura Nakaoka
Shoki Taniguchi
Tomoki Uehara
Jin Inajima
Kohki Tsujimoto
Yusuke Teramura
Satoko Honda
YongGu Shim
Masataka Higashiwaki
author_facet Kura Nakaoka
Shoki Taniguchi
Tomoki Uehara
Jin Inajima
Kohki Tsujimoto
Yusuke Teramura
Satoko Honda
YongGu Shim
Masataka Higashiwaki
author_sort Kura Nakaoka
collection DOAJ
description We demonstrated plasma-assisted molecular beam epitaxy (MBE) growth of high-density nitrogen (N)-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and N radicals. The N density was controlled in a wide range of 1017–1021 cm−3, and single-crystal Ga2O3 thin films with N densities up to 2.9 × 1021 cm−3 were successfully grown. Reflection high-energy electron diffraction images of all MBE-grown N-doped Ga2O3 thin films showed streak patterns, and surface root mean square roughnesses were less than 1.2 nm, indicating that high-quality films were obtained irrespective of the N doping density. Spectroscopic ellipsometry revealed that a N-doped Ga2O3 thin film with N = 2.9 × 1021 cm−3 had a larger refractive index than that of the Ga2O3 film with N = 2.4 × 1018 cm−3, which was probably due to the compositional-level N incorporation of about 4% in the Ga2O3 crystal. The MBE growth technique that enables precise control of the N doping density over five orders of magnitude without compromising crystal quality should be of great help in the future development of various Ga2O3 devices.
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spelling doaj-art-2cf3f3b22d3045b3955aa91c59958b742025-08-20T02:09:58ZengAIP Publishing LLCAPL Materials2166-532X2025-05-01135051117051117-710.1063/5.0258551Plasma-assisted molecular beam epitaxy growth of high-density nitrogen-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and nitrogen radicalsKura Nakaoka0Shoki Taniguchi1Tomoki Uehara2Jin Inajima3Kohki Tsujimoto4Yusuke Teramura5Satoko Honda6YongGu Shim7Masataka Higashiwaki8Department of Physics and Electronics, Osaka Metropolitan University, Sakai, Osaka 599-8531, JapanDepartment of Physics and Electronics, Osaka Metropolitan University, Sakai, Osaka 599-8531, JapanDepartment of Physics and Electronics, Osaka Metropolitan University, Sakai, Osaka 599-8531, JapanDepartment of Physics and Electronics, Osaka Metropolitan University, Sakai, Osaka 599-8531, JapanDepartment of Physics and Electronics, Osaka Metropolitan University, Sakai, Osaka 599-8531, JapanDepartment of Physics and Electronics, Osaka Metropolitan University, Sakai, Osaka 599-8531, JapanDepartment of Physics and Electronics, Osaka Metropolitan University, Sakai, Osaka 599-8531, JapanDepartment of Physics and Electronics, Osaka Metropolitan University, Sakai, Osaka 599-8531, JapanDepartment of Physics and Electronics, Osaka Metropolitan University, Sakai, Osaka 599-8531, JapanWe demonstrated plasma-assisted molecular beam epitaxy (MBE) growth of high-density nitrogen (N)-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and N radicals. The N density was controlled in a wide range of 1017–1021 cm−3, and single-crystal Ga2O3 thin films with N densities up to 2.9 × 1021 cm−3 were successfully grown. Reflection high-energy electron diffraction images of all MBE-grown N-doped Ga2O3 thin films showed streak patterns, and surface root mean square roughnesses were less than 1.2 nm, indicating that high-quality films were obtained irrespective of the N doping density. Spectroscopic ellipsometry revealed that a N-doped Ga2O3 thin film with N = 2.9 × 1021 cm−3 had a larger refractive index than that of the Ga2O3 film with N = 2.4 × 1018 cm−3, which was probably due to the compositional-level N incorporation of about 4% in the Ga2O3 crystal. The MBE growth technique that enables precise control of the N doping density over five orders of magnitude without compromising crystal quality should be of great help in the future development of various Ga2O3 devices.http://dx.doi.org/10.1063/5.0258551
spellingShingle Kura Nakaoka
Shoki Taniguchi
Tomoki Uehara
Jin Inajima
Kohki Tsujimoto
Yusuke Teramura
Satoko Honda
YongGu Shim
Masataka Higashiwaki
Plasma-assisted molecular beam epitaxy growth of high-density nitrogen-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and nitrogen radicals
APL Materials
title Plasma-assisted molecular beam epitaxy growth of high-density nitrogen-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and nitrogen radicals
title_full Plasma-assisted molecular beam epitaxy growth of high-density nitrogen-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and nitrogen radicals
title_fullStr Plasma-assisted molecular beam epitaxy growth of high-density nitrogen-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and nitrogen radicals
title_full_unstemmed Plasma-assisted molecular beam epitaxy growth of high-density nitrogen-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and nitrogen radicals
title_short Plasma-assisted molecular beam epitaxy growth of high-density nitrogen-doped Ga2O3 thin films on Ga2O3 (010) substrates by simultaneously supplying oxygen and nitrogen radicals
title_sort plasma assisted molecular beam epitaxy growth of high density nitrogen doped ga2o3 thin films on ga2o3 010 substrates by simultaneously supplying oxygen and nitrogen radicals
url http://dx.doi.org/10.1063/5.0258551
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