Single photon emitters based on Ni/Si related defects in single crystalline diamond

We present investigations on single Ni/Si related color centers produced via ion implantation into single crystalline type IIa CVD diamond. Testing different ion dose combinations we show that there is an upper limit for both the Ni and the Si dose 10^12/cm^2 and 10^10/cm^2 resp.) due to creation of excess fluorescent background. We demonstrate creation of Ni/Si related centers showing emission in the spectral range between 767nm and 775nm and narrow line-widths of 2nm FWHM at room temperature. Measurements of the intensity auto-correlation functions prove single-photon emission. The investigated color centers can be coarsely divided into two groups: Drawing from photon statistics and the degree of polarization in excitation and emission we find that some color centers behave as two-level, single-dipole systems whereas other centers exhibit three levels and contributions from two orthogonal dipoles. In addition, some color centers feature stable and bright emission with saturation count rates up to 78kcounts/s whereas others show fluctuating count rates and three-level blinking.Comment: 7 pages, submitted to Applied Physics B, revised versio

Ripple topography of ion-beam–eroded graphite: A key to ion-beam–induced damage tracks

The ripple topography of ion-beam–eroded surfaces offers a novel method to determine the shape of collision cascades and the distribution of deposited energy. From the energy dependence of the ripple spacing of Ar+- and Xe+-irradiated graphite surfaces at ion energies between 2 and 50 keV, the relations between mean depth, longitudinal and lateral straggling of the damage cascade were obtained. Their evolution with the ion energy was found to follow power laws for both ion masses and implies an energy-independent lateral spread of the damage cascade, while depth and longitudinal spread scale with the ion energy. This can be explained by the nuclear stopping power being nearly independent of energy in the observed region. High-resolution micrographs of single-ion impacts support this interpretation, as the hillock-shaped surface defects found in the experiments show a lateral extension being independent of the ion energy