Erbium ion implantation into diamond – measurement and modelling of the crystal structure

Abstract

Diamond is proposed as an extraordinary material usable in interdisciplinary fields, especially in optics and photonics. In this contribution we focus on the doping of diamond with erbium as an optically active centre. In the theoretical part of the study based on DFT simulations we have developed two Er-doped diamond structural models with 0 to 4 carbon vacancies in the vicinity of the Er atom and performed geometry optimizations by the calculation of cohesive energies and defect formation energies. The theoretical results showed an excellent agreement between the calculated and experimental cohesive energies for the parent diamond. The highest values of cohesive energies and the lowest values of defect formation energies were obtained for models with erbium in the substitutional carbon position with 1 or 3 vacancies in the vicinity of the erbium atom. From the geometry optimization the structural model with 1 vacancy had an octahedral symmetry whereas the model with 3 vacancies had a coordination of 10 forming a trigonal structure with a hexagonal ring. In the experimental part, erbium doped diamond crystal samples were prepared by ion implantation of Er ions using ion implantation fluences ranging from 1 × 10 ions per cm to 5 × 10 ions per cm. The experimental results revealed a high degree of diamond structural damage after the ion implantation process reaching up to 69% of disordered atoms in the samples. The prepared Er-doped diamond samples annealed at the temperatures of 400, 600 and 800 °C in a vacuum revealed clear luminescence, where the 〈110〉 cut sample has approximately 6-7 times higher luminescence intensity than the 〈001〉 cut sample with the same ion implantation fluence. The reported results are the first demonstration of the Er luminescence in the single crystal diamond structure for the near-infrared spectral region.

Erbium Luminescence Centres in Single- and Nano-Crystalline Diamond—Effects of Ion Implantation Fluence and Thermal Annealing

“…The use of the known minimum-yield depth profiles χ D ( z ), which are deduced from the RBS-aligned spectra, makes it possible to extract the depth profiles of the displaced atoms by iterating the aligned spectrum yield and converting it into the dislocated-atom density using the approach described in [ 36 ]. The RBS channelling spectra of the single-crystalline diamond implanted by Er can be found in [ 29 ], and the extracted displacement atom concentration depth profile is presented in Figure 2 b. The production of the displaced atoms is supposed to be similar for both single- and nano-crystalline diamond structures.…”

“… ( a ) Stopping and Range of Ions in Matter (SRIM)-simulated Er concentration depth profile in a pure diamond structure with a density of 3.5 g·cm −3 and the depth profile of displaced atoms produced in a diamond structure as simulated by SRIM; ( b ) Theoretically determined atomic density depth profile of displaced atoms for different implantation fluences using experimentally-determined channelling spectra of erbium in single-crystalline diamond with the same energy [ 29 ]. …”

“…Concerning the development of photonics and quantum-based networks operating with commercial optical fibres operating in the near-infrared (NIR) region of about 900–2000 nm, it is particularly interesting to study an efficient incorporation of Er into the diamond [ 28 ]. According to the theoretical modelling results, which were done in [ 11 ] as well as in our previous work [ 29 ], the lantahanide ions (Er, Eu, etc.) are able to exist both in substitutional and interstitial positions in diamond without serious parent-diamond structure changes or bond cracking.…”

Emerging rare-earth doped material platforms for quantum nanophotonics

“…One approach is to chemically self-assemble rare-earth complexes on bulk or nano-diamonds before growing a new diamond layer by CVD [122,123]. Another one consists of implanting rare-earth into bulk or nano diamond [124,125]. Rare-earth ion luminescence has been observed with these different methods, with long lifetimes in the case of Eu 3+ ions [122].…”

“…Rare-earth ion luminescence has been observed with these different methods, with long lifetimes in the case of Eu 3+ ions [122]. The lack of well-resolved crystal field structure in the spectra, however, prevents a detailed analysis of the rare-earth local environment and comparison with simulations [122][123][124], which could unambiguously confirm their incorporation into diamonds, is still under debate [123]. High-resolution or coherent spectroscopy has not yet been reported on these systems.…”