BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Electron microscopy studies of semi-conducting materials DTSTART:20230503T143000Z DTEND:20230503T160000Z DTSTAMP:20260731T132044Z UID:31bafaed-8634-4871-8d72-bd0e87225def SEQUENCE:2 CREATED:20230421T150837Z DESCRIPTION:Boron (B) has the potential for generating an intermediate ban d in cubic silicon carbide(3C-SiC)\, turning this material into a highly e fficient absorber for single-junction solarcells. The formation of a deloc alized band demands high concentration of the foreignelement\, but the pre cipitation behavior of B in the 3C polymorph of SiC is not wellknown. Here \, probe-corrected scanning transmission electron microscopy (STEM) andsec ondary-ion mass spectrometry are used to investigate precipitation mechani sms inB-implanted 3C- SiC as a function of temperature. Point-defect clust ering was detectedafter annealing at 1273 K while stacking faults\, B-rich precipitates and dislocationnetworks developed in the 1573 - 1773 K range . The precipitates adopt therhombohedral B13C2 structure and trap B up to 1773 K. Above this temperature\,higher solubility reduces precipitation an d free B diffuses out of the implantation layer.Dopant concentrations of 1 019 at.cm−3 were achieved at 1873 K. The concept of maximizing configura tional entropy to enhance solid-state miscibilityinspires the exploration of unfamiliar composition spaces\, and the popular\, althoughimprecise\, h igh-entropy (HE) designation seems destined to endure. The spotlight hasbe en on the mechanical properties of HE alloys\, but interest in functional behavior isswiftly rising. In particular\, the vast potential of combining metal solid solutions withstructural main group elements to form HE semic onductor compounds is becomingevident. The structure of a (Zn\,Mn)(Fe\,Co\ ,Ni)Sb compound is investigated by powderX-ray diffraction\, STEM coupled to atomically resolved energy dispersive spectroscopy(EDS) and by energy-f iltered convergent-beam electron diffraction (CBED). Distinctionbetween th e 216 (half-Heusler) and 225 (full-Heusler) space groups is hindered by th esimilar scattering power of the transition metals in XRD. However\, the s tructure couldbe deciphered by STEM/EDS with the space group further attes ted by CBED. LAST-MODIFIED:20230421T151811Z LOCATION:Sala de Seminários do DF\, Pavilhão de Física\, 2º piso URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/electron-microscopy-studie s-of-semi-conducting-materials/ X-ALT-DESC;FMTTYPE=text/html:

Boron (B) has the p otential for generating an intermediate band in cubic silicon carbide(3C-S iC)\, turning this material into a highly efficient absorber for single-ju nction solarcells. The formation of a delocalized band demands high concen tration of the foreignelement\, but the precipitation behavior of B in the 3C polymorph of SiC is not wellknown. Here\, probe-corrected scanning tra nsmission electron microscopy (STEM) andsecondary-ion mass spectrometry ar e used to investigate precipitation mechanisms inB-implanted 3C- SiC as a function of temperature. Point-defect clustering was detectedafter anneali ng at 1273 K while stacking faults\, B-rich precipitates and dislocationne tworks developed in the 1573 - 1773 K range.

The precipitates ad opt therhombohedral B13C2 structure and trap B up to 1773 K. Above this te mperature\,higher solubility reduces precipitation and free B diffuses out of the implantation layer.Dopant concentrations of 1019 at.cm−3 were ac hieved at 1873 K. The concept of maximizing configurational entropy to enh ance solid-state miscibilityinspires the exploration of unfamiliar composi tion spaces\, and the popular\, althoughimprecise\, high-entropy (HE) desi gnation seems destined to endure. The spotlight hasbeen on the mechanical properties of HE alloys\, but interest in functional behavior isswiftly ri sing.

In particular\, the vast potential of combining metal soli d solutions withstructural main group elements to form HE semiconductor co mpounds is becomingevident. The structure of a (Zn\,Mn)(Fe\,Co\,Ni)Sb comp ound is investigated by powderX-ray diffraction\, STEM coupled to atomical ly resolved energy dispersive spectroscopy(EDS) and by energy-filtered con vergent-beam electron diffraction (CBED). Distinctionbetween the 216 (half -Heusler) and 225 (full-Heusler) space groups is hindered by thesimilar sc attering power of the transition metals in XRD. However\, the structure co uldbe deciphered by STEM/EDS with the space group further attested by CBED .

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