Quantum Emitter Formation Dynamics and Probing of Radiation-Induced Atomic Disorder in Silicon

Abstract

Near-infrared color centers in silicon are emerging candidates for on-chip integrated quantum emitters, optical-access quantum memories, and sensing. We access ensemble G-color-center formation dynamics and radiation-induced atomic disorder in silicon for a series of megaelectronvolt proton-flux conditions. The photoluminescence results reveal that the G centers are formed more efficiently by pulsed-proton irradiation than by continuous-wave proton irradiation. The enhanced transient excitations and dynamic annealing within nanoseconds allows optimization of the ratio of G-center formation to nonradiative defect accumulation. The G centers preserve narrow line widths of about 0.1 nm when they are generated by moderate pulsed-proton fluences, while the line width broadens significantly as the pulsed-proton fluence increases. This implies vacancy or interstitial clustering by overlapping collision cascades. The tracking of G-center properties for a series of irradiation conditions enables sensitive probing of atomic disorder, serving as a complementary analytical method for sensing damage accumulation. Aided by ab initio electronic structure calculations, we provide insight into the atomic disorder induced inhomogeneous broadening by introducing vacancies, silicon interstitials, and oriented strain fields in the vicinity of a G center. A vacancy leads to a tensile strain and can result in either a red shift or a blue shift of the G-center emission, depending on its position relative to the G center. Meanwhile, Si interstitials lead to compressive strain, which results in a monotonic red shift. High-flux and tunable ion pulses enable the exploration of the fundamental dynamics of radiation-induced defects as well as methods for the optimization of G-center formation and qubit synthesis for quantum information processing.

Solid-State Color Centers for Single-Photon Generation

“…The available studies on the fabrication of the G center have pointed out how post-implantation thermal treatment can represent a limiting factor in realizing large-scale arrays of emitters, since it causes a broadening of the ZPL emission, which is a benchmark in the quality evaluation of the quantum source [129]. The emission broadening also exhibits a dependence on the ion implantation process itself, since broader emissions have been reported for carbon implantation [129] with respect to proton-irradiated samples [130].…”

“…The density of the fabricated G centers and the signal-to-noise ratios of individual emitters presented a direct connection with the annealing conditions as well [129], indicating a progressive dissociation of the defects alongside a decrease in the background signal for a longer annealing duration. Therefore, off-equilibrium fabrication strategies that involve dynamic annealing have been explored as a more valid alternative [130]. Particular care must be taken in how different thermal treatment durations used to supply the thermal budget can affect the evolution and stabilization of the G center with respect to competing defective complexes.…”

Nitrogen-Related Defects in Crystalline Silicon

“…Si has been a dominant material in the semiconductor industry for over six decades. It has a wide range of applications in electronic, microelecronic, and optoelectronic fields and especially for nanoelectronic, nuclear medicine, and sensor and photovoltaic devices [1][2][3][4][5]. Typically, Si-based devices are fabricated on single-crystal Czochralski Si wafers.…”

Carbon-Isovalent Dopant Pairs in Silicon: A Density Functional Theory Study

“…Silicon (Si) is the key semiconductor for integrated circuits, transistors, sensors, detectors, solar cells, as well as for applications related to nuclear medicine, space industry, telecommunications, and quantum computing [1][2][3][4][5]. An important issue in the performance of the devices is the presence of defects which affect their electrical, optical, and mechanical properties [6][7][8][9].…”