arXiv subjects

Valdas Jokubavicius

Publications and source records attributed to Valdas Jokubavicius.

4 recordsLinked to original sources

arXiv2026

Spin-active chlorine-related centers in 4H-SiC with telecom-band emissions

A photoluminescence (PL) and magnetic resonance investigation of a defect in chlorine-implanted 4H-SiC is presented. This Cl-related center emits light at telecom wavelengths with zero-phonon lines in the range 1350-1540 nm. Its four configurations exhibit stable PL spectra characterized by narrow zero-phonon lines. For the two configurations that emit light at the C-band, a Debye-Waller factor in the range 22-25% is estimated. Optically detected magnetic resonance confirms that the Cl-related center is spin active and stable at room temperature with the zero-field splitting in the range of 1.0-1.4 GHz. The combined optical and spin properties suggest this center to be a highly promising candidate for scalable quantum networks.

quant-ph↗

arXiv2018

Boron-doping of cubic SiC for intermediate band solar cells: a scanning transmission electron microscopy study

Boron (B) has the potential for generating an intermediate band in cubic silicon carbide (3C-SiC), turning this material into a highly efficient absorber for single-junction solar cells. The formation of a delocalized band demands high concentration of the foreign element, but the precipitation behavior of B in the 3C polymorph of SiC is not well known. Here, probe-corrected scanning transmission electron microscopy and secondary-ion mass spectrometry are used to investigate precipitation mechanisms in B-implanted 3C-SiC as a function of temperature. Point-defect clustering was detected after annealing at 1273 K, while stacking faults, B-rich precipitates and dislocation networks developed in the 1573 - 1773 K range. The precipitates adopted the rhombohedral B13C2 structure and trapped B up to 1773 K. Above this temperature, higher solubility reduced precipitation and free B diffused out of the implantation layer. Dopant concentrations E19 at.cm-3 were achieved at 1873 K.

cond-mat.mtrl-sci↗

arXiv2018

Wafer scale growth and characterization of edge specific graphene nanoribbons

One of the ways to use graphene in field effect transistors is to introduce a band gap by quantum confinement effect [1]. That is why narrow graphene nanoribbons (GNRs) with width less than 50nm are considered to be essential components in future graphene electronics. The growth of graphene on sidewalls of SiC(0001) mesa structures using scalable photolithography was shown to produce high quality GNR with excellent transport properties [2-7]. Such epitaxial graphene nanoribbons are very important in fundamental science but if GNR are supposed to be used in advanced nanoelectronics, high quality thin (<50nm) nanoribbons should be produced on a large (wafer) scale. Here we present a technique for scalable template growth of high quality GNR on Si-face of SiC(0001) and provide detailed structural information along with transport properties. We succeeded to grow GNR along both [1-100] and [11-20] crystallographic directions. The quality of the grown nanoribbons was confirmed by comprehensive characterization with high resolution STM, dark field LEEM and transport measurements.

cond-mat.mes-hall↗

arXiv2017

Isolated spin qubits in SiC with a high-fidelity infrared spin-to-photon interface

The divacancies in SiC are a family of paramagnetic defects that show promise for quantum communication technologies due to their long-lived electron spin coherence and their optical addressability at near-telecom wavelengths. Nonetheless, a mechanism for high-fidelity spin-to-photon conversion, which is a crucial prerequisite for such technologies, has not yet been demonstrated. Here we demonstrate a high-fidelity spin-to-photon interface in isolated divacancies in epitaxial films of 3C-SiC and 4H-SiC. Our data show that divacancies in 4H-SiC have minimal undesirable spin-mixing, and that the optical linewidths in our current sample are already similar to those of recent remote entanglement demonstrations in other systems. Moreover, we find that 3C-SiC divacancies have millisecond Hahn-echo spin coherence time, which is among the longest measured in a naturally isotopic solid. The presence of defects with these properties in a commercial semiconductor that can be heteroepitaxially grown as a thin film on shows promise for future quantum networks based on SiC defects.

quant-ph↗