With great pleasure we present this Topical Section of Physica status solidi (a) showcasing an exciting research in the field of diamond science and technology. Diamond is an attractive material not only for basic science but also for innovative technical applications such as quantum technologies, energy transformation and storage, biomedical imaging and treatment. As pointed out by the establishment of a flagship program by the EU, quantum technologies are one of the major future research directions. Diamond can take centre stage in this field due to its unique properties and the existence of colour centres such as the NV, the SiV and other group 4 vacancy centres. These not only can be used as sensors for magnetic and electric fields but also for quantum information technology. However, progress in this field relies on substantial advances in the production of highly controlled diamond materials using chemical vapour deposition (CVD) or high pressure high temperature (HPHT) with low defect density. Besides, the development of diamond based devices for high‐power applications requires the ultimate control of the materials properties as well.

Another important direction of diamond research is the synthesis and application of functional diamond nanoparticles for biomedical and other life science applications. Highly specific luminescence labels as well as vehicles for drug delivery are being developed while working on the prevention of non‐specific interactions with biological matter. Electrochemical and photochemical applications of various forms of diamond have equally entered the stage as the unique properties of diamond enable unprecedented chemistry on its surface using direct photochemical reduction or the electrochemical formation of useful chemical building blocks.

All of this needs to be accompanied by in‐depth materials characterization and the development of technologies for the deterministic structuring of diamond at the nano or even atomic scale.

The 25^th anniversary edition of the SBDD workshop featured all the mentioned aspects of diamond research. Held in March 2020 in Hasselt (Belgium), it eventually happened to be the last on‐site conference of the diamond community before the pandemic situation prevented personal meetings for scientific exchange and interaction.

This special issue reflects the broad variety of aspects from all areas of diamond research including growth, characterization and applications that have been discussed in Hasselt.

We are pleased to highlight the Feature Article number 2000614 by Sébastien Pezzagna and colleagues on the charge assisted engineering of colour centres. In this feature article, the authors emphasise the importance of a deterministic formation of colour centres in diamond and discuss the necessity of a full understanding of the underlying principles of defect generation for not only spatial control but also with regard to defects and impurities. They look at different approaches to charge vacancies, pin the Fermi level etc., and finally discuss parameters for an optimal formation of colour centres in different diamond substrates. Together with other progress in the addressing of individual centres and the coupling to nuclear spins, they conclude, that a diamond based quantum computer is within a reach.

We hope that this Feature Article and the other articles of this special issue will keep the discussion of current research topics in the field of diamond vibrant and will inspire research to come, both in the field of diamond but also in neighbouring areas.

Würzburg and Hasselt, February 2021.

Anke Krueger and Paulius Pobedinskas

Guest Editors

我们非常高兴地介绍这一物理状态专题部分（a）展示了在钻石科学和技术领域的激动人心的研究。金刚石不仅对基础科学而且对于创新技术应用（例如量子技术，能量转换和存储，生物医学成像和治疗）都是有吸引力的材料。正如欧盟制定的一项旗舰计划所指出的那样，量子技术是未来的主要研究方向之一。钻石由于其独特的性能以及诸如NV，SiV和其他第4组空缺中心之类的色中心的存在，可以在这一领域占据中心地位。这些不仅可以用作磁场和电场的传感器，还可以用作量子信息技术。然而，该领域的进展依赖于使用化学气相沉积（CVD）或缺陷密度低的高压高温（HPHT）生产高度受控的金刚石材料的实质性进展。此外，开发用于大功率应用的基于金刚石的设备还需要对材料特性进行最终控制。

金刚石研究的另一个重要方向是用于生物医学和其他生命科学应用的功能性金刚石纳米颗粒的合成和应用。在致力于防止与生物物质的非特异性相互作用的同时，正在开发高度特异性的发光标签以及用于药物递送的载体。各种形式的钻石在电化学和光化学方面的应用已进入同一个阶段，因为钻石的独特性能可以通过直接光化学还原或电化学形成有用的化学构造基团在其表面上实现空前的化学反应。

所有这些都需要伴随着深入的材料表征和用于确定纳米或什至原子级金刚石确定性结构的技术的发展。

在25^日的SBDD车间的周年纪念版精选钻石研究的所有上述方面。该会议于2020年3月在比利时哈瑟尔特（Hasselt）举行，在大流行形势阻止个人会议进行科学交流和互动之前，它恰好是钻石界的最后一次现场会议。

本期专刊反映了钻石研究各个领域的广泛方面，包括在哈瑟尔特（Hasselt）中讨论的生长，表征和应用。

我们很高兴地强调SébastienPezzagna及其同事在色心中心的辅助充电技术方面的特色文章编号2000614。在这篇专题文章中，作者强调了确定性形成钻石色心的重要性，并讨论了充分理解缺陷产生的基本原理的必要性，这些缺陷不仅用于空间控制，还涉及缺陷和杂质。他们研究了不同的电荷空位，固定费米能级等方法，并最终讨论了在不同金刚石基底中最佳形成色心的参数。他们总结说，在解决单个中心问题以及与核自旋耦合方面取得了其他进展，他们得出结论，基于钻石的量子计算机已经可以触及。

我们希望这篇专题文章和本期特刊的其他文章能够使对钻石领域当前研究话题的讨论保持活跃，并能激发对钻石领域以及周边地区的研究的到来。

2021年2月，维尔茨堡和哈瑟尔特

Anke Krueger和Paulius Pobedinskas

客座编辑