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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2023
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2308.15779 |
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| _version_ | 1866909971267977216 |
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| author | An, Su Young Lee, Hyunkyu Beak, Gunhoon Jo, Hyeonoh Kim, Jae Hun Ha, Jongwoo Yang, Jieun Dong, Changwook Choi, Jaewu Lim, Joonwon Kim, Chinkyo |
| author_facet | An, Su Young Lee, Hyunkyu Beak, Gunhoon Jo, Hyeonoh Kim, Jae Hun Ha, Jongwoo Yang, Jieun Dong, Changwook Choi, Jaewu Lim, Joonwon Kim, Chinkyo |
| contents | The crystallographic orientation of films grown on 2D-masked substrates is often used to infer the pathway among remote, van der Waals, and thru-hole (pinhole-seeded) epitaxy. However, attribution of a specific growth mechanism based on orientation can be ambiguous unless mask continuity and substrate pre-treatment are evaluated within a single process window. We compare GaN grown under identical conditions on four m-plane sapphire templates: (i) bare, (ii) "graphene-grown" (high-temperature Ar/H2 with CH4 on), (iii) "anneal-only" (high-temperature Ar/H2 with CH4 off), and (iv) graphene oxide spin-coated and reduced on pristine sapphire. GaN selects (103) on graphene-grown and anneal-only m-plane sapphire, selects (100) on bare m-plane sapphire, and is predominantly (100) with a minority (103) on graphene oxide spin-coated and reduced/pristine m-plane sapphire. High-resolution TEM shows that, on partly graphene-covered samples, nucleation occurs on exposed sapphire (thru-hole), not on graphene, providing mechanism evidence independent of orientation. Within this window, the substrate surface state set by high-temperature Ar/H2 pre-treatment (rather than mask continuity) primarily governs orientation, while open-area effects can play a secondary role. Thus, preferred orientation alone may not determine the growth mechanism; mask continuity and substrate pre-treatment must be explicitly controlled when using orientation as evidence for mechanism assignment. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2308_15779 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Orientation disparity in GaN/graphene/$m$-sapphire: control-based re-examination of thru-hole epitaxy An, Su Young Lee, Hyunkyu Beak, Gunhoon Jo, Hyeonoh Kim, Jae Hun Ha, Jongwoo Yang, Jieun Dong, Changwook Choi, Jaewu Lim, Joonwon Kim, Chinkyo Materials Science Applied Physics The crystallographic orientation of films grown on 2D-masked substrates is often used to infer the pathway among remote, van der Waals, and thru-hole (pinhole-seeded) epitaxy. However, attribution of a specific growth mechanism based on orientation can be ambiguous unless mask continuity and substrate pre-treatment are evaluated within a single process window. We compare GaN grown under identical conditions on four m-plane sapphire templates: (i) bare, (ii) "graphene-grown" (high-temperature Ar/H2 with CH4 on), (iii) "anneal-only" (high-temperature Ar/H2 with CH4 off), and (iv) graphene oxide spin-coated and reduced on pristine sapphire. GaN selects (103) on graphene-grown and anneal-only m-plane sapphire, selects (100) on bare m-plane sapphire, and is predominantly (100) with a minority (103) on graphene oxide spin-coated and reduced/pristine m-plane sapphire. High-resolution TEM shows that, on partly graphene-covered samples, nucleation occurs on exposed sapphire (thru-hole), not on graphene, providing mechanism evidence independent of orientation. Within this window, the substrate surface state set by high-temperature Ar/H2 pre-treatment (rather than mask continuity) primarily governs orientation, while open-area effects can play a secondary role. Thus, preferred orientation alone may not determine the growth mechanism; mask continuity and substrate pre-treatment must be explicitly controlled when using orientation as evidence for mechanism assignment. |
| title | Orientation disparity in GaN/graphene/$m$-sapphire: control-based re-examination of thru-hole epitaxy |
| topic | Materials Science Applied Physics |
| url | https://arxiv.org/abs/2308.15779 |