Modelarea proprietatilor semiconductoare ale nitrurii cubice de bor pentru aplicatii avansate


Project Director: Dr. Sergiu Nistor

Project ID: 152 din 12.07.2017 (PN-III-P4-ID-PCE-2016-0079)

Project Director: Dr. Vasile Sergiu NISTOR

Project Type: National

Project Program: PCE

Finanatat de:

Romanian National Authority for Scientific Research, UEFISCDI

Contractor:

National Institute of Materials Physics (NIMP)

Project Status: In progress

Data de incepere: Miercuri, 12 iulie, 2017

Data de finalizare: Marti, 31 decembrie, 2019

Rezumatul proiectului:

Nitrura de bor cubica (cBN), ca material semiconductor avand banda interzisa dintre cele mai mari (6.3eV)V, prezinta o combinatie extraordinara de proprietati fizice, comparabile si chiar superioare diamantului, care il recomanda ca pe un material  exceptional pentru un numar mare de aplicatii: LED-uri la lungimi de unda mici (< 300nm), laseri cu semiconductori, detectori optici, sau dispozitive de temperatura, frecventa si putere inalte si mai recent, si mai recent, ca o alternativa la sistemul diamant – centri (NV-) pentru calculatoare cuantice. Utilizarea industriala a cBN este insa impiedicata de absenta de cunostiinte stiintifice privind proprietatile la nivel atomic a impuritatilor ca defecte de retea, esentiala pentru intelegerea si controlul proprietatilor lui macroscopice. Studii anterioare prin rezonanta paramagnetica electronica (RPE) au aratat ca aceata lipsa de informatii privind propietatile atomice ale defectelor active electro-optic  in cBN se datoreaza efectelor de agregare ale impuritatilor, care modifica puternic starile cuantice ale defectelor de impuritate izolate. Scopul proiectului propus este de a intelege procesele de agregare a defectelor punctuale legate de impuritati, care apar  in timpul sintezei cBN cristalin la temperaturi si presiuni inalte, de a dezvolta proceduri si modalitati de obtinere a unei distributii uniforme a acestor defecte prin post-tratamente termo-chimice si de iradiere, de a investiga si intelege proprietatile individuale (structura atomica locala, proprietatile electronice cuantice, proprietatile optice si magnetice) a defectelor de retea asociate impuritatilor, pentru a controla proprietatile macroscopice optice si electrice pentru diverse aplicatii. In cadrul proiectului vor fi utilizate tehnici experimentale de cel mai inalt nivel, cu implicarea unor specialisti de talie modiala in domeniile spectroscopiei EPR si optice, a analizelor microstructurale si sintezei de materiale, cu experienta in studiul cBN si diamantului.

Obiectivul principal al proiectului consta in investigarea prezentei si naturii defectelor paramagnetice asociate impuritatilor, prin complectarea si extinderea portofelului de date existent. Prin utilizarea unor tehnici experimentale avansate complementare, se vor obtine date stiintifice esentiale privind  structura atomica locala a defectelor intrinseci si asociate impuritatilor din nitrura cubica de bor semiconductoare, in corelare cu starile electronice localizate in structura de benzi asociate. Se vor mai determina influenta acestor defecte asupra proprietatilor macroscopice de interes aplicativ, in particular a proprietatilor structurale, optice si electrice si a modului in care acestea pot fi modificate sub influenta factorilor externi: campuri de radiatii si/sau tratamente termochimice.

Etapa 1.  Determinarea structurii locale, atomice si a proprietatilor electronice ale defectelor intrinseci si asociate impuritatilor din cBN cristalin colorat galben-auriu si intunecat, preparat prin sinteza la presiuni si temperaturi inalte, proprietati determinate din studii correlate EPR, microstructurale si studii optice. (Activitati care continua in etapa 2).

Perioada: 12.07.2017-31.12.2017

Etapa 2.  Determinarea structurii locale, atomice si a proprietatilor electronice ale defectelor intrinseci si asociate impuritatilor din cBN cristalin colorat galben-auriu si intunecat, preparat prin sinteza la presiuni si temperaturi inalte, proprietati determinate din studii correlate EPR, microstructurale si studii optice (continuare etapa  1). Schimbarea starii de agregare a impuritatilor si defectelor associate in cBN cristalin colorat galben-auriu si intunecat prin tratamente termochimice si/sau iradiere. Identificarea si caracterizarea starilor de impuritati dispersate  rezultate.

Perioada: 01.01.2018-31.12.2018

Etapa 3. Schimbarea starii de agregare a impuritatilor si defectelor paramagnetice asociate din cBN cristalin colorat galben-auriu si intunecat prin tratamente termochimice si/sau iradiere . Identificarea si caracterizarea starilor de impuritate dispersate (continuare etapa 2). - Caracterizarea prin EPR si spectroscopie optica a impuritatilor atomice dispersate si defectelor de retea asociate din cristalele de cBN.

Perioada: 01.01.2019-31.12.2019

Dr. Vasile Sergiu Nistor, Senior Researcher I, Project Director

Dr. Leona Cristina Nistor, Senior Researcher I

Fiz. Alexandra Camelia Joita, Scientific Researcher assistant, PhD student

Dr. Aurel Mihai Vlaicu, Senior Researcher III

Dr. Mariana Stefan, Senior Researcher II

Dr. Raluca Florina Negrea, Scientific Researcher

Dr. Daniela Ghica, Senior Researcher II

Dr. Ioana Dorina Vlaicu, Senior Researcher

Fiz. Cristian Radu, Scientific Researcher Assistant, MSc student

PhD adviser  of  Alexandra Camelia Joita , PhD student at the Doctoral School of Physics, Faculty of Physics, University of Bucharest, with direct participation in all research activities of the present project, including preparation of manuscripts for publication, as well as in participation with presentation of communications at the following International Conferences of Physics

  • The 9th International Conference on Advanced Materials: ROCAM 2017 – Bucharest, 11-14 July 2017 (oral presentation).
  • The 10th International Conference on Luminescent Detectors and Transformers of Ionizing Radiation, LUMDETR-2018, Prague, 9-14 Sept. 2018 (poster presentation)
  • The 16th International Conference on Nanosciences & Nanotechnologies, NN19, Thessaloniki, 2-5 iulie 2019 (poster presentation).
  • Conference of the Romanian Electron Microscopy Society, CREMS, Poiana Brasov, 23-25 octombrie 2019. (poster presentation)

Papers in internationally recognized (ISI) journals

  1. "Production and annealing of the paramagnetic defects in as-grown and oxygen doped floating zone silicon irradiated with high fluence 3.5 MeV and 27 MeV electrons”, A. C. Joita and S. V. Nistor, Mater. Science in Semicond. Processing 83, 1-11 (2018)
  2. "Structure of defects in semiconductor crystalline cubic boron nitride. A microstructural and micro analytical investigation". L. C. Nistor,  A. M. Vlaicu and S.V. Nistor, Radiation Measurements, 123, 78-82 (2019).
  3. “Presence and distribution of impurity defects in crystalline cubic boron nitride. A spectroscopic study”. S. V.  Nistor, L. C.  Nistor, A. M. Vlaicu and A. C. Joita, Radiation Measurements, 123, 21-25 (2019).
  4. “Investigating photo-active ESR centers in semiconductors with a high intensity monochromatic in-situ illumination set-up”.  S. V. Nistor and A. C. Joita, Applied Magnetic Resonance (Springer), propus spre publicare.

Presentations at conferences:

  1. "ESR of irradiation point defects in pure and 17O doped Si-FZ single crystals at high doses of 3.5 MeV electrons", A. C. Joita, S. V. Nistor, R. Radu and I. Pintilie, The 9th International Conference on Advanced Materials: ROCAM 2017 – Bucharest, 11-14 July 2017 (oral presentation).
  2.  “About the nature and distribution of defects in crystalline cubic boron nitride wide band-gap semiconductor”., S. V. Nistor, L. C. Nistor, A. M. Vlaicu and A.C.Joita, The 10th International Conference on Luminescent Detectors and Transformers of Ionizing Radiation, LUMDETR-2018, Prague, 9-14 Sept. 2018 (oral presentation).
  3. “Structure of defects in semiconductor cubic boron nitride. A microstructural and microanalytical investigation”, L. C. Nistor, A. M. Vlaicu, R. F. Negrea and S. V. Nistor, The 10th International Conference on Luminescent Detectors and Transformers of Ionizing Radiation, LUMDETR-2018, Prague, 9-14 Sept. 2018 (poster presentation).
  4. “Impurity type defects in crystalline cubic boron nitride. A correlated ESR, ESM and CL study on cBN crystals”, A. C. Joita, S. V. Nistor, L. C. Nistor and A. M. Vlaicu, The 10th International Conference on Luminescent Detectors and Transformers of Ionizing Radiation, LUMDETR-2018, Prague, 9-14 Sept. 2018 (poster presentation).
  5. “Origin of the collective magnetism in cubic ZnS quantum dots doped with Mn2+ From myths to the harsh reality.”, S. V. Nistor, The 16th International Conference on Nanosciences & Nanotechnologies, NN19, Thessaloniki, 2-5 iulie 2019 (invited-oral presentation).
  6. “Nanostructured impurities in superhard crystalline cubic boron nitride”, C. Nistor, S.V. Nistor, A.C. Joita, The 16th International Conference on Nanosciences & Nanotechnologies, NN19, Thessaloniki, 2-5 iulie 2019 (poster presentation).
  7. “Nanoaggregates of impurities in superhard cubic boron nitride crystals”, C. Joita, S. V. Nistor, L. C. Nistor, R. F. Negrea, The 16th International Conference on Nanosciences & Nanotechnologies, NN19, Thessaloniki, 2-5 iulie 2019 (poster presentation).
  8. “Analytical HRTEM/STEM study of impurity defects in cubic boron nitride crystals”, C. Nistor, S.V. Nistor, R.F. Negrea, Conference of the Romanian Electron Microscopy Society, CREMS, Poiana Brasov, 23-25 octombrie 2019 (oral presentation).
  9. “Atomic impurity defects in crystalline cubic boron nitride semiconductor”, V. Nistor, L.C. Nistor, A.C. Joita, Conference of the Romanian Electron Microscopy Society, CREMS, Poiana Brasov, 23-25 octombrie 2019. (poster presentation).

Dr. Sergiu Vasile NISTOR

Senior Researcher I,

National Institute of Materials Physics

Atomistilor 405A, Bucharest-Magurele,

Romania 077125;

Phone: + 40 21 369 0170/190

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