IndexExperimental ProceduresActivation EnergyRaman Mapping MeasurementsIncreasing Defects in CrystalsCathodoluminescence (CL) MeasurementsSummary and Future PerspectivesExperimental ProceduresExperiments were conducted to obtain B-doped samples using the same experimental setup as Figure 4 1 with the replacement of phosphoric acid with boric acid solution (2%). The dopant liquid was prepared by dissolving 2 g of boric acid H3BO3 in 1000 g of distilled water for 45 minutes, then using ultrasound for 1 minute to ensure complete solubility as 2% is the maximum solubility that can be achieved at room temperature . The liquid absorption coefficient and reflectance were also calculated by applying the same experiment as in Figure ‎4 2 and using Equation ‎4 1 through Equation ‎4 4 for the calculations. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay The experiment produced an absorption coefficient of approximately 0.27763 cm -1 which confirms the low absorption of the boric acid solution. This means that almost 94.5% of the incident power is transmitted in case of dopant depth (z=2 mm) above the substrate. This confirms the validity of the liquid to be used as a dopant source without affecting the power radiated by the laser since no significant losses occur during transmission through the acid itself. After immersing the diamond substrate in 2% boric acid, ArF excimer laser irradiations were carried out at different fluences, repetition rates and number of laser shots as shown in the irradiation matrix of Figure 4. 8. Measurements were conducted of electrical conductivity, Raman measurement and cathodoluminescence (CL) for the sample after irradiation. After acid treatment to remove conductivity for the sample surface, measurements were conducted to test the electrical behavior of the irradiated areas. No electrodes were deposited, the propeller heads were directly in contact with the irradiated point. IV measurements showed a clear decrease in resistance with increasing number of laser shots, as shown in Figure ‎4-9, similar to experimental results using liquid phosphoric acid. The electrical resistivity also decreases further with increasing temperature, which evidently indicates that the surface layer generated by irradiation is semiconductor and the conductivity does not result from any residual graphite on the surface. Activation Energy The activation energy of boron at low levels of boron is approximately 0.37 eV. [ ] and decreasing to almost zero demonstrating metallic conductivity at very high doping levels [ ]. It was also previously found that the experimentally detected activation energy of boron in the samples decreased with an increase in the B/C ratio [ ]. While decreasing activation energy increases the number of charge carriers at reasonable temperature, the mobility of charge carriers decreases, limiting conductivity and usefulness in some device structures, and this problem is yet to be faced by CVD diamond [7 ]. in our experiment the activation energy was estimated from the temperature dependence of electrical conduction via the Arrhenius diagram as shown in Figure ‎4 10. The activation energy estimated from the temperature dependence of electrical conduction decreases with increasing of the number of shots, which could be associated with an increase in the B/C ratio. The linearity agrees to some extent with the result obtained from the Arrhenius plot for a diamond containing natural boron andfound it linear with an MSE of 1 meV [7]. The electrical response of boron-doped epitaxial films can be quite complicated, and the type of conductivity is still being studied. Raman mapping measurements To study the influence of structural defects on Raman spectra, confocal Raman measurements were performed as shown in Figure 4 11: Typical Raman spectra measured on irradiated areas a) 5 j/cm2, 5 Hz, 1000 shots b) 5 j/cm2, 20 Hz, 50 shots c) non-irradiated background. .Raman spectroscopy is a powerful non-destructive method for evaluating diamond quality. The Raman peak of diamond is sensitive to lattice structure, deformation and impurities [ , ]. Crystalline defects could be observed using analysis based on full width at half maximum (FWHM) and peak shift mapping [,,]. For p+ diamond, the Raman peak of the diamond is broadened and shifted to a lower wavenumber as the amount of boron increases [ , ]. Raman spectra were measured using the Nanophoton RAMAN-touch confocal Raman microscope system with an Nd:YAG laser source operating at a wavelength of 532 nm and laser power of 5.5 W. All Raman spectra were measured before any acid treatment on the sample and at room temperature with a fixed exposure time of 0.5 seconds and a fixed integration number. For Raman mapping analysis, the peak position and FWHM values ​​were used to create the mapping images as shown in Figure ‎4 12. It is known that the first-order diamond peak at 1333 cm–1 (the phonon optical zone center ) usually decreases in intensity, shifts downward in wavenumber, and broadens asymmetrically with an increase in boron content [ ]. Raman showed a single peak centered at 1333 cm-1 due to diamond, but no peaks due to graphite or AC. The mapping showed changes in amplitude depending on doping conditions, while peak shift and FWHM mapping remained intact. The change in intensity could be related to many factors: Loss of crystallinity due to lattice distortion. electron-electron scattering contribution that increases with charge concentration. Increase of defects in the crystal Furthermore, there may be other possibilities of intensity change which will be further investigated with other measurements. It has been reported that the position of the Raman peak is shifted due to the lattice deformation generated around the dislocations. The observed displacement was no greater than +/- 1.0 cm-1 from the diamond peak location of 1333 cm-1, which corresponds to a compressive/tensile stress of tens to hundreds of MPa. Large lattice deformation of the order of GPa is typically observed in polycrystalline or nanocrystalline diamonds, but rarely generated in single-crystalline diamond [ ] and this may be why no shit peak is observed. it was not possible to observe the asymmetric Raman peak of the diamond due to the Fano effect, which could be due to slight doping. according to previous studies, an asymmetric shape appeared with the CVD-doped diamond due to the Fano effect caused by the strong boron doping accompanied by a small appearance of peaks at the lower Raman shift. this has been attributed to the local vibration modes of the boron pairs, but in our technique we use different dopants and incorporation methods other than diamond CVD. Cathodoluminescence (CL) Measurements Cathodoluminescence (CL) spectroscopy was used to study exciton recombination. CL is a useful tool for investigating electronic states in diamond due to lattice imperfections such as impurities, point defects anddislocations [ ]. the appearance of CL bands with energies lower than the band-gap energy (5.47 eV) in CVD diamond indicates the existence of energy states characteristic of lattice imperfections as, a very broad visible band (A band), is commonly observed in diamond, it originates from dislocations and is sometimes decorated by boron or other impurities [ ]. In contrast, diamond without such CL bands means it contains only a low density of lattice imperfections [ ]. Previously reported results regarding CVD diamond stated that the minimum energy of an electron-hole pair in diamond, the band gap, is 5.49 eV. The energy that binds the electron to the hole of the free exciton is 0.08 eV; the minimum energy of a free exciton is therefore 5.41 eV. Since diamond has an indirect band gap, the luminescence of electron-hole pairs and free excitons requires the emission of one or more phonons for each photon. The most intense free exciton luminescence line, at 5.27 eV, requires emission of a 0.14 eV transverse optics (TO) phonon. The neutral boron acceptor in lightly boron-doped diamond gives rise to a bound exciton state with a binding energy 0.05 eV greater than the binding energy of the free exciton and a total energy above the ground state of 5.36 eV. The phonon line TO of the acceptor-bound exciton in lightly boron-doped diamond therefore occurs at 5.22 eV [ ]. As shown in Figure 4.13 Cathodoluminescence (CL) measurements were conducted after surface treatment of the H2 plasma to avoid charging. in the irradiated area it was possible to clearly observe the bound exciton (BE) due to the B atoms incorporated by substitution into the diamond lattices. However its intensity is too small to confirm doping, still similar result obtained for lightly doped CVD diamond [ ].Summary and future prospects The laser beam was partially characterized to understand its behavior and effect on the diamond substrate. The heat generated by irradiation was found to increase with increasing fluence. The melting depth and heat distribution were also strongly affected by changing the laser fluence. Experimentally measured reflectivity demonstrated that the fusion duration is approximately equal to the duration of the laser pulse, and the reflectivity increases with increasing fluence, which indicates whether partial or total ablation has occurred following irradiation. Combining this result and that of the simulation, we believe that increasing the substrate's ambient temperature, laser beam fluence, laser pulse duration, and ambient pressure control the total energy required to melt the film and increase the duration of the film. fusion to facilitate doping, so performing the experiment in a heated vacuum chamber and increasing the pulse duration is expected to improve the process greatly. Single crystal diamond samples were immersed in phosphoric acid/boric acid and irradiated at different fluences, number of shots and different repetition rates. The substrate was examined optically after irradiation and no significant damage was observed. The samples were cleaned to remove the generated graphite layer and the electrical behavior of the irradiated area was tested and the conductivity was confirmed with the laser parameters. Electrical conductivity improved with increasing fluence, number of shots, repetition rate, and temperature indicating that the area generated by irradiation is semiconductive. The depth profile also confirmed the incorporation of phosphorus into the diamond up to a thickness of 30 nm. The champions.