BEGIN:VCALENDAR VERSION:2.0 METHOD:PUBLISH PRODID:-//Missouri State University/Calendar of Events//EN CALSCALE:GREGORIAN X-WR-TIMEZONE:America/Chicago BEGIN:VTIMEZONE TZID:America/Chicago BEGIN:DAYLIGHT TZOFFSETFROM:-0600 TZOFFSETTO:-0500 DTSTART:20070311T020000 RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU TZNAME:CDT END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:-0500 TZOFFSETTO:-0600 DTSTART:20071104T020000 RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU TZNAME:CST END:STANDARD END:VTIMEZONE BEGIN:VEVENT UID:b9da6235-a127-4567-a8b6-c3d987d43e76.232313@calendar.missouristate.edu CREATED:20231105T010435Z LAST-MODIFIED:20231105T010435Z LOCATION:Kemper Hall 204 SUMMARY:PAMS Seminar: "Epitaxial AlScN Films and Nanowires for Ferroelectr ic Random-Access Memory Applications" by Dr. Andrew Meng DESCRIPTION:Dr. Andrew MengUniversity of MissouriDepartment of Physics and Astronomy\n\n\nAbstract:AlN-based alloys are promising candidate ferroel ectric materials for neuromorphic computing applications. Compared to tra ditional complex oxide ferroelectrics\, AlN-based materials exhibit relat ively higher remanent polarizations and have potential for compatibility with Si processing. We report growth of epitaxial wurtzite AlN and AlScN thin films on Si(111) substrates with a wide range of Sc concentrations u sing ultra-high vacuum reactive sputtering. We also report growth of sing le crystal AlScN nanowires on TiN buffered Si(111) substrates. Sc alloyin g in AlN enhances piezoelectricity and induces ferroelectricity\, and epi taxial thin films and nanowires facilitate systematic structure-based inv estigations of this important and emerging class of materials. Two main e ffects are observed as a function of increasing Sc concentration in AlScN thin films. First\, increasing crystalline disorder is observed together with a structural transition from wurtzite to rocksalt at ~30 at% Sc. Se cond\, nanoscale compositional segregation consistent with spinodal decom position occurs at intermediate compositions\, before the wurtzite to roc ksalt phase boundary is reached. Lamellar features arising from compositi on fluctuations are correlated with polarization domains in AlScN\, sugge sting that composition segregation can influence ferroelectric properties . The present results provide a route to the creation of single crystal A lScN films on Si(111)\, as well as a means for self-assembled composition modulation.While increasing Sc incorporation increases mosaic disorder\, nanowire growth provides a means to reduce mosaic disorder through finit e size effects. We demonstrate ferroelectric properties of AlScN nanowire s as measured by piezoforce response microscopy. Finally\, we report elec trical characteristics of AlScN films with ~12 at% Sc with different grow th conditions on TiN buffered Si(111) substrates. The data are consistent with electrical conduction arising from point defects formed during AlSc N film growth. The results provide a structure-based approach to minimizi ng electrical leakage in AlScN devices\, which is one of the main challen ges in these materials. X-ALT-DESC;FMTTYPE=text/html:<html><head><title></title></head><body><p><b >Dr.&nbsp\;Andrew Meng</b><br><b>University of&nbsp\;Missouri</b><br><b>D epartment of Physics and Astronomy</b></p>\n<p>Abstract:<br>AlN-based all oys are promising candidate ferroelectric materials for neuromorphic comp uting applications. Compared to traditional complex oxide ferroelectrics\ , AlN-based materials exhibit relatively higher remanent polarizations an d have potential for compatibility with Si processing. We report growth o f epitaxial wurtzite AlN and AlScN thin films on Si(111) substrates with a wide range of Sc concentrations using ultra-high vacuum reactive sputte ring. We also report growth of single crystal AlScN nanowires on TiN buff ered Si(111) substrates. Sc alloying in AlN enhances piezoelectricity and induces ferroelectricity\, and epitaxial thin films and nanowires facili tate systematic structure-based investigations of this important and emer ging class of materials. Two main effects are observed as a function of i ncreasing Sc concentration in AlScN thin films. First\, increasing crysta lline disorder is observed together with a structural transition from wur tzite to rocksalt at ~30 at% Sc. Second\, nanoscale compositional segrega tion consistent with spinodal decomposition occurs at intermediate compos itions\, before the wurtzite to rocksalt phase boundary is reached. Lamel lar features arising from composition fluctuations are correlated with po larization domains in AlScN\, suggesting that composition segregation can influence ferroelectric properties. The present results provide a route to the creation of single crystal AlScN films on Si(111)\, as well as a m eans for self-assembled composition modulation.While increasing Sc incorp oration increases mosaic disorder\, nanowire growth provides a means to r educe mosaic disorder through finite size effects. We demonstrate ferroel ectric properties of AlScN nanowires as measured by piezoforce response m icroscopy. Finally\, we report electrical characteristics of AlScN films with ~12 at% Sc with different growth conditions on TiN buffered Si(111) substrates. The data are consistent with electrical conduction arising fr om point defects formed during AlScN film growth. The results provide a s tructure-based approach to minimizing electrical leakage in AlScN devices \, which is one of the main challenges in these materials.</p></body></ht ml> DTSTART;TZID=America/Chicago:20231109T160000 DTEND;TZID=America/Chicago:20231109T170000 SEQUENCE:0 URL:https://physics.missouristate.edu/seminars.htm CATEGORIES:Public,Alumni,Current Students,Faculty,Future Students,Staff END:VEVENT END:VCALENDAR