IN THE NAME OF ALLAH, THE MOST MERCIFUL AND COMPASSIONATE

Transcription

1 IN THE NAME OF ALLAH, THE MOST MERCIFUL AND COMPASSIONATE

2 Ion Beam Analysis of Diamond Thin Films Sobia Allah Rakha Experimental Physics Labs

3 Outline Diamond Nanostructures Deposition of Diamond Nanostructures Ion Solid Interaction Elastic Recoil Detection (ERD) Analysis ERD Analysis of Diamond Films Conclusions

4 Diamond Nanostructures

5 Nanocrystalline Diamond (NCD) NCD films appear to be industrially acceptable alternative of monocrystalline diamonds. Having the outstanding properties of CVD diamond but ultra-smooth surface. Nano diamond is expected to be an effective FE material due to the NEA.

6 Results (HFCVD):( Deposition in H 2 rich CVD H 2 /CH 4 :98.5/1.5,Ts=1023 K, p= 30 Torr Sobia A. R. Yu G. J., Current Applied Physics 9 (2009)

7 Results (HFCVD):( Deposition in H 2 rich CVD Microcrystalline Sample Sub-microcrystalline Sample Nanocrystalline Sample

8 Results (HFCVD):( Deposition in H 2 rich environment High nucleation rate limited the grain size within the range of few nanometers. C 2 dimer causes high nucleation rate which critically influences the growth parameters. C 2 dimer increases sharply by increasing filament temperature which resulted in nanosized crystallites.

9 Ion Solid Interaction

10 Ion Solid Interactions Nuclear Energy Loss Electronic Energy Loss An ion entering in a solid find atoms with electrons orbiting around in their orbits

11 Ion-atom interactions Secondary Ion Mass Spectrometry (SIMS) Secondary ions Ion beam Auger electrons X- rays Auger Electron Spectrometry (AES) Particle Induced X-ray Emission (PIXE) Elastic Recoil Detection (ERD) Backscattered particles Particle emission γ- rays Nuclear Reaction Analysis (NRA) Rutherford Backscattering Spectrometry (RBS) Ion-nucleus interactions Ion Beam Analysis

12 4UH Pelletron accelerator to procure the beam of charged particles, in LNAT (SINAP).

13 Elastic Recoil Detection

14 Elastic Recoil Detection A Convenient Method for Depth Profiling of Light Elements, Especially Hydrogen.

15 For better experimental statistic Samples should be of minimized surface roughness. Use highly collimated incident beams to minimize the loss of resolution caused by angular spread. Use Kapton and other polymers as range foil materials that have superior thickness uniformity.

16 Applications of ERDA For the quantitative information of hydrogen. Capable of Profiling 1H, 2D and 3T in one turn. To study the growth mechanism at the initial stage of diamond deposition by comparing the hydrogen concentration of the growth surface. To study incorporation of hydrogen both in bonded and non-bonded form present in non crystalline and defective regions of films.

17 ERD Analysis of Diamond Films

18 Schematic of Experimental Setup

19 Important parameters and capabilities of ERD Probe ion Ion energy Beam current Detector Depth resolution Range Foil He 1 4 MeV na SSBD (silicon surface barrier detector) ~ 700 Å. Mylar or other polymers Sensitivity ~ 0.5 atomic % to 0.1 atomic %. Analyzable depth ~ Å

20 Results : Incorporation of Hydrogen in Diamond thin films Channel Determination of H: Simulation of data using QUARK-ERD Counts Energy [ MeV ] Channel Simulation Experiment Channel Counts Counts Energy [ MeV ] Energy [ MeV ] Simulation Experiment Simulation Experiment

21 Results : Incorporation of Hydrogen in Diamond thin films Determination of H: Si standard with Known H content.

22 Results : Incorporation of Hydrogen in Diamond thin films Crystalline size (nm) 1 um ± 20 nm Hydrogen concentration vs. the crystalline size and I nd to I d ratios H (From Simulation) total concentration atoms/cm 3 H (From Standard) concentration atoms/cm (0.8%) I nd / I d (Diamond Peak Position) 0.24 (1330) 300 nm ± 20 nm 50 nm ± 20 nm (1.3%) 0.81 (1332) (3.3%) 1.12 (1335) Sobia A.R., Diamond & Related Materials 18 (2009)

23 Conclusions Diamond films in the grain size from micro to nanometer were synthesized in Hydrogen rich environments. Ion Solid Interactions. Elastic Recoil Detection Analysis of Diamond Films. Ion Beam Analysis Techniques proves helpful for the study of growth kinematics of the growing structures.

24 THANK YOU for your Attention