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Hydrogen analysis in diamond like carbon by elastic recoil detection
Kim, Joonkon,Choi, Han Woo,Woo, Hyung Joo,Kim, Gi Dong Elsevier 2010 CURRENT APPLIED PHYSICS Vol.10 No.2
<P><B>Abstract</B></P><P>Among the available surface analytic instruments, elastic recoil detection (ERD) is known as a reliable method for hydrogen analysis. Since conventional fluence determination <I>i.e.</I> beam current integration is incredible at a large tilt angle, ion fluence is determined by the scattering spectrum that is simultaneously measured with recoil spectrum. However scattering cross sections deviate Rutherford values in the ERD energy of 1–3MeV. Carbon scattering cross section is different from Rutherford value for higher beam energies over 1.8MeV. As a result hydrogen content is exaggerated when fluence is determined by carbon matrix because of fluence underestimation due to lower value of scattering cross section than Rutherford’s. Therefore in order to quantify hydrogen in diamond like carbon (DLC) incident beam energy lower than 1.6MeV should be used where carbon scattering cross sections are well agreed with Rutherford’s.</P>
Joonkon Kim,Chulhun Eum,Wan Hong 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.43 No.42
During ion-beam irradiation, an electric potential is induced on the surface of an insulator sample owing to electric charge buildup. Because this uncontrollable built-up voltage causes energy uctuations of the incoming ions and the exiting charged particles, the uncertainty in ion-beam analyses, such as Rutherford backscattering spectrometry and elastic recoil detection increases. In order to suppress the charge buildup eect, we deposited a thin gold lm on the sample surface. Using a He beam, and measured the built-up voltage at the insulator surface as a function of the Au film thickness. We determined the minimum thickness necessary to suppress such an effect for several insulators samples.
Hydrogen analysis in diamond like carbon by elastic recoil detection
Joonkon Kim,Han Woo Choi,Hyung Joo Woo,Gi Dong Kim 한국물리학회 2010 Current Applied Physics Vol.10 No.2
Among the available surface analytic instruments, elastic recoil detection (ERD) is known as a reliable method for hydrogen analysis. Since conventional fluence determination i.e. beam current integration is incredible at a large tilt angle, ion fluence is determined by the scattering spectrum that is simultaneously measured with recoil spectrum. However scattering cross sections deviate Rutherford values in the ERD energy of 1–3 MeV. Carbon scattering cross section is different from Rutherford value for higher beam energies over 1.8 MeV. As a result hydrogen content is exaggerated when fluence is determined by carbon matrix because of fluence underestimation due to lower value of scattering cross section than Rutherford’s. Therefore in order to quantify hydrogen in diamond like carbon (DLC) incident beam energy lower than 1.6 MeV should be used where carbon scattering cross sections are well agreed with Rutherford’s.
Fabrication of Silicon-Vacancy Color Centers in Nanodiamonds by using Si-Ion Implantation
Hyeongkwon Kim,Hyeyeon Kim,Jaeyong Lee,Weon Cheol Lim,John A. Eliades,Joonkon Kim,Jonghan Song,석재권 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.5
Si ions 2.3 MeV are implanted into nanodiamonds (NDs) at doses of 11012 11015 ions/cm2. The ion implantation not only creates silicon-vacancy (SiV) color centers but also reduces the size of the NDs from 50 nm to 10 nm. As the Si dose is increased up to 1 1013 ions/cm2, the luminescence from the nitrogen-vacancy (NV) color centers in the ND initially increases. At higher dose rates, the luminescence from the NV color centers decreases. Due to the differences in the minimum ND size required for stable luminescence, the zero phonon line (ZPL) of the SiV color center appears after the luminescence from the NV center decreases dramatically. The ZPLs from both centers become almost negligible after Si ions have been implanted at doses higher than 5 1014 ions/cm2. These observations are explained by the reduced size of the NDs and the number of implanted Si ions, which is estimated based on SRIM simulations.
김준곤,우형주,최한우,김기동,홍완,Kim Joonkon,Woo H. J.,Choi H. W.,Kim G. D.,Hong W. The Korean Vacuum Society 2005 Applied Science and Convergence Technology Vol.14 No.2
지난 10년 동안 유전체 내부에 형성된 나노미터 크기의 규소알갱이는 발광센터로서 주목 받아왔다 나노미터 크기인 결정질 규소의 엑시토닉 전자-홀의 쌍들이 발광결합에 기여한다고 여겨진다. 그러나 규소결정에 존재하는 여러가지 결함들은 비발광 천이의 경로가 되어 나노규소결접립의 발광천이와 경쟁하여 발광효율을 저하시키는 요인이 된다. 이러한 결정 결함들은 고온 열처리과정에서 대부분 소멸되나 $1000^{\circ}C$ 이상의 공정 에서도 나노규소와 유전체의 계면에 존재하는 결함들은 나노규소결정립의 발광을 억제하게 된다. 일반적으로 수소로서 규소결정립의 계면을 마감처리하게 되면 규소결정립의 발광효율이 획기적으로 향상되나 불행하게도 매질 내 수소의 높은 이동성으로 말미암아 후속 열처 리 과정에서 수소마감효과는 쉽게 손실된다. 따라서 본 연구에서는 온도가역적인 수소 대신 인을 이온주입 방법으로 첨가하여 수소와 같은 계면 마감효과를 얻으며 또한 후속 고온공정 에 대한 내구력을 증대시켰다. 모재인 산화규소 기판에 400keV, $1\times10^{17}\; Si/cm^2$와 그 주위에 균일한 함량을 도핑하기 위하여 다중에너지의 인을 주입하였다. 규소와 인을 이온주입 후 Ar 분위기에서 $1100^{\circ}C$ , 두 시간의 후열처리를 통하여 규소결정립을 형성하였으며 향상된 내열효과를 시험하기 위하여 Ar 분위기에서 $1000^{\circ}C$까지 열처리하였다. 인으로 마감된 나노미터 크기인 규소 결정립의 향상된 광-발광(PL)효과와 감쇄시간, 그리고 발광파장의 변화에 대하여 논의하였다. Nanometric crystalline silicon (no-Si) embedded in dielectric medium has been paid attention as an efficient light emitting center for more than a decade. In nc-Si, excitonic electron-hole pairs are considered to attribute to radiative recombination. However the surface defects surrounding no-Si is one of non-radiative decay paths competing with the radiative band edge transition, ultimately which makes the emission efficiency of no-Si very poor. In order to passivate those defects - dangling bonds in the $Si:SiO_2$ interface, hydrogen is usually utilized. The luminescence yield from no-Si is dramatically enhanced by defect termination. However due to relatively high mobility of hydrogen in a matrix, hydrogen-terminated no-Si may no longer sustain the enhancement effect on subsequent thermal processes. Therefore instead of easily reversible hydrogen, phosphorus was introduced by ion implantation, expecting to have the same enhancement effect and to be more resistive against succeeding thermal treatments. Samples were Prepared by 400 keV Si implantation with doses of $1\times10^{17}\;Si/cm^2$ and by multi-energy Phosphorus implantation to make relatively uniform phosphorus concentration in the region where implanted Si ions are distributed. Crystalline silicon was precipitated by annealing at $1,100^{\circ}C$ for 2 hours in Ar environment and subsequent annealing were performed for an hour in Ar at a few temperature stages up to $1,000^{\circ}C$ to show improved thermal resistance. Experimental data such as enhancement effect of PL yield, decay time, peak shift for the phosphorus implanted nc-Si are shown, and the possible mechanisms are discussed as well.