Perovskite (structure): Difference between revisions

Perovskites can be deposited as epitaxial thin films on top of other perovskites,<ref>{{cite journal |last1=Martin |first1=L.W. |last2=Chu |first2=Y.-H. |last3=Ramesh |first3=R. |title=Advances in the growth and characterization of magnetic, ferroelectric, and multiferroic oxide thin films |journal=Materials Science and Engineering: R: Reports |date=May 2010 |volume=68 |issue=4–6 |pages=89–133 |doi=10.1016/j.mser.2010.03.001|s2cid=53337720 |url=http://www.escholarship.org/uc/item/1gm2n89d }}</ref> using techniques such as [[pulsed laser deposition]] and [[molecular-beam epitaxy]]. These films can be a couple of nanometres thick or as small as a single unit cell.<ref>{{cite journal |last1=Yang |first1=G.Z |last2=Lu |first2=H.B |last3=Chen |first3=F |last4=Zhao |first4=T |last5=Chen |first5=Z.H |title=Laser molecular beam epitaxy and characterization of perovskite oxide thin films |journal=Journal of Crystal Growth |date=July 2001 |volume=227-228 |issue=1–4 |pages=929–935 |doi=10.1016/S0022-0248(01)00930-7|bibcode=2001JCrGr.227..929Y }}</ref> The well-defined and unique structures at the interfaces between the film and substrate can be used for interface engineering, where new types properties can arise.<ref>{{cite journal |last1=Mannhart |first1=J. |last2=Schlom |first2=D. G. |title=Oxide Interfaces--An Opportunity for Electronics |journal=Science |date=25 March 2010 |volume=327 |issue=5973 |pages=1607–1611 |doi=10.1126/science.1181862|pmid=20339065 |bibcode=2010Sci...327.1607M |s2cid=206523419 }}</ref> This can happen through several mechanisms, from mismatch strain between the substrate and film, change in the oxygen octahedral rotation, compositional changes, and quantum confinement.<ref>{{cite journal |last1=Chakhalian |first1=J. |last2=Millis |first2=A. J. |last3=Rondinelli |first3=J. |title=Whither the oxide interface |journal=Nature Materials |date=24 January 2012 |volume=11 |issue=2 |pages=92–94 |doi=10.1038/nmat3225|pmid=22270815 |bibcode=2012NatMa..11...92C }}</ref> An example of this is LaAlO₃ grown on SrTiO₃, where the [[lanthanum aluminate-strontium titanate interface|interface can exhibit conductivity]], even though both LaAlO₃ and SrTiO₃ are non-conductive.<ref>{{cite journal |last1=Ohtomo |first1=A. |last2=Hwang |first2=H. Y. |title=A high-mobility electron gas at the LaAlO₃/SrTiO₃ heterointerface |journal=Nature |date=January 2004 |volume=427 |issue=6973 |pages=423–426 |doi=10.1038/nature02308|pmid=14749825 |bibcode=2004Natur.427..423O |s2cid=4419873 }}</ref> Another example is SrTiO₃ grown on LSAT ((LaAlO₃)_0.3 (Sr₂AlTaO₆)_0.7) or DyScO₃ can morph the incipient ferroelectric into a [[Ferroelectricity|ferroelectric]] at room temperature through the means of epitaxially applied biaxial [[Stress (mechanics)|strain]].<ref name="Haeni2004">{{Cite journal |last1=Haeni |first1=J. H. |last2=Irvin |first2=P. |last3=Chang |first3=W. |last4=Uecker |first4=R. |last5=Reiche |first5=P. |last6=Li |first6=Y. L. |last7=Choudhury |first7=S. |last8=Tian |first8=W. |last9=Hawley |first9=M. E. |last10=Craigo |first10=B. |last11=Tagantsev |first11=A. K. |last12=Pan |first12=X. Q. |last13=Streiffer |first13=S. K. |last14=Chen |first14=L. Q. |last15=Kirchoefer |first15=S. W. |date=2004 |title=Room-temperature ferroelectricity in strained SrTiO₃ |url=https://www.nature.com/articles/nature02773 |journal=Nature |language=en |volume=430 |issue=7001 |pages=758–761 |doi=10.1038/nature02773 |hdl=2027.42/62658 |s2cid=4420317 |issn=1476-4687|hdl-access=free }}</ref> The lattice mismatch of GdScO₃ to SrTiO₃ (+1.0 %) applies [[Tensile strain|tensile]] stress resulting in a decrease of the out-of-plane lattice constant of SrTiO₃, compared to LSAT (–0.9 %), which epitaxially applies [[Compressive stress|compressive]] stress leading to an extension of the out-of-plane lattice constant of SrTiO₃ (and subsequent increase of the in-plane lattice constant).<ref name="Haeni2004" />

In 1997, scintillation properties of cerium doped lutetium aluminum perovskite (LuAP:Ce) single crystals were reported.<ref name="Moszynski1997">{{cite journal|last1=Moszynski|first1=M|title=Properties of the new LuAP:Ce scintillator|journal=Nuclear Instruments and Methods in Physics Research A|date=11 January 1997|volume=385|issue=1|pages=123–131|doi=10.1016/S0168-9002(96)00875-3|bibcode=1997NIMPA.385..123M|doi-access=free}}</ref> The main property of those crystals is a large mass density of 8.4 g/cm³, which gives short X- and gamma-ray absorption length. The scintillation light yield and the decay time with Cs¹³⁷ radiation source are 11,400 photons/MeV and 17 ns, respectively.<ref>{{Cite journal|last1=Maddalena|first1=Francesco|last2=Tjahjana|first2=Liliana|last3=Xie|first3=Aozhen|last4=Arramel|last5=Zeng|first5=Shuwen|last6=Wang|first6=Hong|last7=Coquet|first7=Philippe|last8=Drozdowski|first8=Winicjusz|last9=Dujardin|first9=Christophe|last10=Dang|first10=Cuong|last11=Birowosuto|first11=Muhammad Danang|date=February 2019|title=Inorganic, Organic, and Perovskite Halides with Nanotechnology for High–Light Yield X- and γ-ray Scintillators|journal=Crystals|language=en|volume=9|issue=2|pages=88|doi=10.3390/cryst9020088|doi-access=free}}</ref> Those properties made LUAP:Ce scintillators attractive for commercials and they were used quite often in high energy physics experiments. Until eleven years later, one group in Japan proposed Ruddlesden-Popper solution-based hybrid organic-inorganic perovskite crystals as low-cost scintillators.<ref name="Kishimoto2008">{{cite journal|last1=Kishimoto|first1=S|title=Subnanosecond time-resolved x-ray measurements using an organic-inorganic perovskite scintillator|journal=Appl. Phys. Lett.|date=29 December 2008|volume=93|issue=26|page=261901|doi=10.1063/1.3059562|bibcode=2008ApPhL..93z1901K}}</ref> However, the properties were not so impressive in comparison with LuAP:Ce. Until the next nine years, the solution-based hybrid organic-inorganic perovskite crystals became popular again through a report about their high light yields of more than 100,000 photons/MeV at cryogenic temperatures.<ref name="Birowosuto2016">{{cite journal|last1=Birowosuto|first1=Muhammad Danang|title=X-ray Scintillation in Lead Halide Perovskite Crystals|journal=Sci. Rep.|date=16 November 2016|volume=6|page=37254|doi=10.1038/srep37254|pmid=27849019|pmc=5111063|arxiv=1611.05862|bibcode=2016NatSR...637254B}}</ref> Recent demonstration of perovskite nanocrystal scintillators for X-ray imaging screen was reported and it is triggering more research efforts for perovskite scintillators.<ref name="QChen2018">{{cite journal|last1=Chen|first1=Quishui|title=All-inorganic perovskite nanocrystal scintillators|journal=Nature|date=27 August 2018|volume=561|issue=7721|pages=88–93|doi=10.1038/s41586-018-0451-1|pmid=30150772|bibcode=2018Natur.561...88C|s2cid=52096794}}</ref> Layered Ruddlesden-Popper perovskites have shown potential as fast novel scintillators with room temperature light yields up to 40,000 photons/MeV, fast decay times below 5 ns and negligible afterglow.<ref name=":0" /><ref name=":1" /> In addition this class of materials have shown capability for wide-range particle detection, including [[alpha particle]]s and thermal [[neutron]]s.<ref>{{Cite journal|last1=Xie|first1=Aozhen|last2=Hettiarachchi|first2=Chathuranga|last3=Maddalena|first3=Francesco|last4=Witkowski|first4=Marcin E.|last5=Makowski|first5=Michał|last6=Drozdowski|first6=Winicjusz|last7=Arramel|first7=Arramel|last8=Wee|first8=Andrew T. S.|last9=Springham|first9=Stuart Victor|last10=Vuong|first10=Phan Quoc|last11=Kim|first11=Hong Joo|date=2020-06-24|title=Lithium-doped two-dimensional perovskite scintillator for wide-range radiation detection|journal=Communications Materials|language=en|volume=1|issue=1|page=37|doi=10.1038/s43246-020-0038-x|bibcode=2020CoMat...1...37X|issn=2662-4443|doi-access=free}}</ref>