Crystallization properties of arsenic doped GST alloys
<p dir="ltr">We present the enhanced properties observed in the phase change memory alloy Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> (GST) when doped with arsenic. Although arsenic is known as a toxic element, our observations show that significant...
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| مؤلفون آخرون: | , , |
| منشور في: |
2019
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| _version_ | 1864513520797745152 |
|---|---|
| author | Vinod E. Madhavan (8136774) |
| author2 | Marcelo Carignano (1390921) Ali Kachmar (1609192) K. S. Sangunni (18618943) |
| author2_role | author author author |
| author_facet | Vinod E. Madhavan (8136774) Marcelo Carignano (1390921) Ali Kachmar (1609192) K. S. Sangunni (18618943) |
| author_role | author |
| dc.creator.none.fl_str_mv | Vinod E. Madhavan (8136774) Marcelo Carignano (1390921) Ali Kachmar (1609192) K. S. Sangunni (18618943) |
| dc.date.none.fl_str_mv | 2019-09-10T03:00:00Z |
| dc.identifier.none.fl_str_mv | 10.1038/s41598-019-49168-z |
| dc.relation.none.fl_str_mv | https://figshare.com/articles/journal_contribution/Crystallization_properties_of_arsenic_doped_GST_alloys/25907800 |
| dc.rights.none.fl_str_mv | CC BY 4.0 info:eu-repo/semantics/openAccess |
| dc.subject.none.fl_str_mv | Engineering Materials engineering Phase change memory alloy Ge2Sb2Te5 (GST) Arsenic doping Thermal stability Transition temperature Amorphous phase Crystalline phase |
| dc.title.none.fl_str_mv | Crystallization properties of arsenic doped GST alloys |
| dc.type.none.fl_str_mv | Text Journal contribution info:eu-repo/semantics/publishedVersion text contribution to journal |
| description | <p dir="ltr">We present the enhanced properties observed in the phase change memory alloy Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> (GST) when doped with arsenic. Although arsenic is known as a toxic element, our observations show that significant improvement can be obtained in GST systems on thermal stability, transition temperature between amorphous and crystalline phases and switching behaviors when doping with arsenic. Though both the GST and arsenic doped GST are amorphous in the as-deposited state, only GST alloy turns to crystalline NaCl-type structure after annealing at 150 °C for 1 h. Results from the resistance versus temperature study show a systematic increase in the transition temperature and resistivity in the amorphous and crystalline states when the arsenic percentage in the GST alloy increases. The crystallization temperature (T<sub>c</sub>) of (GST)<sub>0.85</sub>As<sub>0.15</sub> is higher than the T<sub>c</sub> observed in GST. Optical band gap (E<sub>opt</sub>) values of the as-deposited films show a clear increasing trend; 0.6 eV for GST to 0.76 eV for (GST)<sub>0.85</sub>As<sub>0.15</sub>. The decreases in E<sub>opt</sub> for the samples annealed at higher temperatures shows significant optical contrast between the as-deposited and annealed samples. Though all (GST)<sub>1−x</sub>As<sub>x</sub> alloys show memory switching behaviors, threshold switching voltages (V<sub>T</sub>) of the studied alloys show an increasing trend with arsenic doping. For (GST)<sub>0.85</sub>As<sub>0.15</sub>, V<sub>T</sub> is about 5.2 V, which is higher than GST (4.0 V). Higher transition temperature and higher threshold switching values show arsenic doping in GST can enhance the memory device properties by improving the thermal stability and data readability. Understanding the doping effect on the GST is important to understand its crystallization properties. Structure properties of amorphous GST, Ge<sub>2</sub>Sb<sub>2−0.3</sub>As<sub>0.3</sub>Te<sub>5</sub> and (GST)<sub>0.85</sub>As<sub>0.15</sub> models were studied using first principles molecular dynamics simulations, compared their partial radial distribution functions, and q parameter order. Arsenic doping into GST features interesting structural and electronic effects revealed by the radial distribution functions, q order parameter and band gap value, in line with the experimental findings.</p><p dir="ltr"><br></p><h2>Other Information</h2><p dir="ltr">Published in: Scientific Reports<br>License: <a href="https://creativecommons.org/licenses/by/4.0" target="_blank">https://creativecommons.org/licenses/by/4.0</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1038/s41598-019-49168-z" target="_blank">https://dx.doi.org/10.1038/s41598-019-49168-z</a></p> |
| eu_rights_str_mv | openAccess |
| id | Manara2_cadd148c3ae9c5afb30ea950d1eb9419 |
| identifier_str_mv | 10.1038/s41598-019-49168-z |
| network_acronym_str | Manara2 |
| network_name_str | Manara2 |
| oai_identifier_str | oai:figshare.com:article/25907800 |
| publishDate | 2019 |
| repository.mail.fl_str_mv | |
| repository.name.fl_str_mv | |
| repository_id_str | |
| rights_invalid_str_mv | CC BY 4.0 |
| spelling | Crystallization properties of arsenic doped GST alloysVinod E. Madhavan (8136774)Marcelo Carignano (1390921)Ali Kachmar (1609192)K. S. Sangunni (18618943)EngineeringMaterials engineeringPhase change memory alloyGe2Sb2Te5 (GST)Arsenic dopingThermal stabilityTransition temperatureAmorphous phaseCrystalline phase<p dir="ltr">We present the enhanced properties observed in the phase change memory alloy Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub> (GST) when doped with arsenic. Although arsenic is known as a toxic element, our observations show that significant improvement can be obtained in GST systems on thermal stability, transition temperature between amorphous and crystalline phases and switching behaviors when doping with arsenic. Though both the GST and arsenic doped GST are amorphous in the as-deposited state, only GST alloy turns to crystalline NaCl-type structure after annealing at 150 °C for 1 h. Results from the resistance versus temperature study show a systematic increase in the transition temperature and resistivity in the amorphous and crystalline states when the arsenic percentage in the GST alloy increases. The crystallization temperature (T<sub>c</sub>) of (GST)<sub>0.85</sub>As<sub>0.15</sub> is higher than the T<sub>c</sub> observed in GST. Optical band gap (E<sub>opt</sub>) values of the as-deposited films show a clear increasing trend; 0.6 eV for GST to 0.76 eV for (GST)<sub>0.85</sub>As<sub>0.15</sub>. The decreases in E<sub>opt</sub> for the samples annealed at higher temperatures shows significant optical contrast between the as-deposited and annealed samples. Though all (GST)<sub>1−x</sub>As<sub>x</sub> alloys show memory switching behaviors, threshold switching voltages (V<sub>T</sub>) of the studied alloys show an increasing trend with arsenic doping. For (GST)<sub>0.85</sub>As<sub>0.15</sub>, V<sub>T</sub> is about 5.2 V, which is higher than GST (4.0 V). Higher transition temperature and higher threshold switching values show arsenic doping in GST can enhance the memory device properties by improving the thermal stability and data readability. Understanding the doping effect on the GST is important to understand its crystallization properties. Structure properties of amorphous GST, Ge<sub>2</sub>Sb<sub>2−0.3</sub>As<sub>0.3</sub>Te<sub>5</sub> and (GST)<sub>0.85</sub>As<sub>0.15</sub> models were studied using first principles molecular dynamics simulations, compared their partial radial distribution functions, and q parameter order. Arsenic doping into GST features interesting structural and electronic effects revealed by the radial distribution functions, q order parameter and band gap value, in line with the experimental findings.</p><p dir="ltr"><br></p><h2>Other Information</h2><p dir="ltr">Published in: Scientific Reports<br>License: <a href="https://creativecommons.org/licenses/by/4.0" target="_blank">https://creativecommons.org/licenses/by/4.0</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1038/s41598-019-49168-z" target="_blank">https://dx.doi.org/10.1038/s41598-019-49168-z</a></p>2019-09-10T03:00:00ZTextJournal contributioninfo:eu-repo/semantics/publishedVersiontextcontribution to journal10.1038/s41598-019-49168-zhttps://figshare.com/articles/journal_contribution/Crystallization_properties_of_arsenic_doped_GST_alloys/25907800CC BY 4.0info:eu-repo/semantics/openAccessoai:figshare.com:article/259078002019-09-10T03:00:00Z |
| spellingShingle | Crystallization properties of arsenic doped GST alloys Vinod E. Madhavan (8136774) Engineering Materials engineering Phase change memory alloy Ge2Sb2Te5 (GST) Arsenic doping Thermal stability Transition temperature Amorphous phase Crystalline phase |
| status_str | publishedVersion |
| title | Crystallization properties of arsenic doped GST alloys |
| title_full | Crystallization properties of arsenic doped GST alloys |
| title_fullStr | Crystallization properties of arsenic doped GST alloys |
| title_full_unstemmed | Crystallization properties of arsenic doped GST alloys |
| title_short | Crystallization properties of arsenic doped GST alloys |
| title_sort | Crystallization properties of arsenic doped GST alloys |
| topic | Engineering Materials engineering Phase change memory alloy Ge2Sb2Te5 (GST) Arsenic doping Thermal stability Transition temperature Amorphous phase Crystalline phase |