O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy Preparation and characterization of single-crystal diamond for improved particle detectors O.Lysenko, N.Novikov, V.Grushko, O.Zanevskiy, M.Serga, V.Lysakovskiy, S.Ivakhnenko V.Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine

Single crystal diamond O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy Motivation property silicon Polycrystalline diamond Single crystal diamond detector operation band gap [eV] breakdown voltage [V/cm] intrinsic resistivity [Ω/cm] electron mobility [cm2/Vs] hole mobility [cm2/Vs] 1.12 3∙105 2.3 ∙ 105 1350 480 5.4 0.5 ∙ 106 >> 106 1800 1000 5.48 107 >> 1011 1900 – 4500 1800 – 3500 + high T operation +high field operation + low leakage current + fast signal Evolution of detectors for experiments at high luminosity colliders Silicon Polycrystalline diamond films CVD single crystal diamond Ultrapure HPHT single crystal diamond with controlled physical properties

Difficulties on the way towards a perfect diamond detector O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy Difficulties on the way towards a perfect diamond detector Ideally diamond detector is just a solid state ionization chamber In reality next problems exit: nitrogen limits the life time of free charge carriers defective surface layer creates undesirable space charge To improve the quality of diamond detectors following approach is used: Specified conditions of HPHT diamond growth with low defect content Thermobaric processing of HPHT diamonds Cut diamond plate from defined area of the crystal

Idea The band structure of diamond O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy Idea The band structure of diamond S. Painter, D. E. Ellis, A. R. Lubinsky, Ab Initio Calculations of the Electronic Structure and Optical Properties of Diamond Using the Discrete Variational Method, Phys. Rev. B, vol. 4, p. 3610, 1971

Approach 1) Synthesis of colorless large HPHT IIa diamonds O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy Approach 1) Synthesis of colorless large HPHT IIa diamonds 2) Cut diamond plate from defined area of the crystal 3) Specified conditions of crystal growth

Termobaric processing O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy Termobaric processing Nitrogen is the main impurity in diamond C-defects (nitrogen in replacing position) prevail in synthetic diamonds Thermobaric processing allows to convert C-defects into (less harmful) A-defects P = 6.7GPa T = 1800C t = 4 hours Conditions of thermobaric processing: Types of defects are seen in IR absorbtion spectra: C-defect: 1135cm-1 A-defect: 1282cm-1

O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy HPHT diamond plates

Future work O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy Nitrogen vacancies are actually fluorescent: when green light strikes them, the nitrogen atom’s two excitable unpaired electrons glow a brilliant red. The realization of electrically driven single-photon source based on a single neutral nitrogen-vacancy centre in a diamond diode structure. a) L. Jiang, ect Repetitive Readout of a Single Electron Spin via Quantum Logic. with Nuclear Spin Ancillae Science 326, 267 (2009). b) N. Mizuochi, ect Electrically driven single-photon source at room temperature in diamond. Nature Photonics, Volume 6, Issue 5, pp. 299-303 (2012).

O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy Summary HPHT single crystal diamond is a good candidate for diamond detectors of particles. HPHT diamond plates have advantages over commonly accepted CVD plates due to absence of highly defective intercrystallite boundaries. Specified conditions of crystal growth allows to obtain detectors with very low defect content thus avoiding undesirable space charge. Cutting a diamond plate from specific zone of the crystal with extremely low nitrogen content allows to produce detectors with contain of nitrogen less then 1015 atoms per cubic centimetre. The structure of single-crystal diamond with a low nitrogen content should be Control using NV-centers approach. When exposed to the NV-centers by the specific electromagnetic radiation, they become a single-photon sources. According to the number of observed single-photon sources it can be concluded about the concentration of nitrogen and accumulated radiation. Thank you