# Defects in Silicon Carbide as Quantum Qubits: Recent Advances in Defect Engineering
## 1 Introduction
Several comprehensive reviews have been published, covering various aspects of quantum defect physics, material platforms, and semiconductor qubits. Some of the most notable reviews include the following:  
Figure 1: The total number of publications on quantum qubits. Data are extracted from the Web of Science Core Collection with the topic “quantum qubits”. * [PERSON] et al. [22], \"Material Platforms for Defect Qubits and Single-Photon Emitters\": This review provides a broad overview of the solid-state systems pivotal for spin-based quantum technologies. It discusses advancements in solid-state spins and single-photon emitters across multiple host materials, including diamond, silicon carbide (SiC), hexagonal boron nitride (hBN), silicon, and two-dimensional semiconductors. The authors also emphasize the role of theoretical and computational methods in guiding experimental progress in defect-based quantum technologies;
* [PERSON] et al. [23], \"Semiconductor Qubits in Practice\": This paper provides a detailed analysis of semiconductor-based qubits, covering their implementation in quantum computing, quantum simulation, quantum sensing, and quantum networking. The review highlights the key challenges and progress in integrating these systems into scalable quantum architectures;
* [PERSON] et al. [24], \"Quantum Guidelines for Solid-State Spin Defects\": This review offers a set of broad guidelines for the development and application of solid-state spin defects in quantum information processing. The authors discuss defect properties, host material characteristics, engineering opportunities, and potential pathways for improving coherence times, optical properties, and scalability. Given the existence of these in-depth and widely cited review articles, a legitimate question arises: What unique contribution does this paper make, and how does it differentiate itself from prior work? Unlike the broader scope of the aforementioned reviews, this paper is specifically tailored to early-career experimental researchers focusing on the controllable formation of color centers in SiC for quantum qubit applications. Instead of attempting to cover the entire landscape of SiC quantum applications, this review adopts a focused and practical approach by emphasizing defect engineering techniques and their relevance to quantum qubit performance. This review provides an overview of the fabrication methods for generating SiC defects, including irradiation, ion implantation, and laser processing [14; 15; 16; 17; 18]. Moreover, many existing reviews are either theory oriented [2; 4] or focused on the comprehensive material characterization that includes a whole variety of techniques, such as low-temperature photoluminescence (PL), electron paramagnetic resonance (EPR), and optically detected magnetic resonance (ODMR) techniques [22; 23; 25; 26; 27; 28]. This easy-to-follow review aims to bridge the gap between theoretical studies and comprehensive material characterization by strictly focusing on the intermediate step, defect creation. The paper is structured as follows. Section 2 introduces the fundamental principles of quantum qubits, outlining the criteria that a defect center must satisfy to function as a viable qubit. Section 3, the core of this review, focuses on the selected SiC defects and their formation via different experimental methods. Section 4 provides a summary and conclusion. By maintaining a well-defined and specialized focus, this review serves as a valuable resource for experimentalists looking to advance their expertise in SiC-based quantum defect fabrication. It ensures that researchers can efficiently access the most relevant information to accelerate their work on next-generation quantum technologies.