Advanced Inorganic Semiconductor Materials, 2nd Edition

1. Introduction

Building upon our previous edition [1], this second edition of “Advanced Inorganic Semiconductor Materials” continues to explore the evolution of materials chemistry and physics in the realm of semiconductors [2,3]. This edition reflects a vibrant cross-section of contemporary research and review contributions focused on the synthesis, functional design, and applications of inorganic semiconductors. With emerging priorities such as energy sustainability, biocompatibility, spintronics, and optoelectronics [4], the 11 featured articles reflect the extraordinary depth and breadth of this field.

2. Semiconductor Architectures and Optical Phenomena

Two-dimensional metal-halide perovskites [5] are now redefining RTP. In a standout study (Contribution 1 [6]), the strategic tuning of alkyl chain lengths in organic amines resulted in perovskites (4-POMACC and 4-POEACC) exhibiting highly efficient RTP, particularly 4-POMACC with an extended lifetime (254 ms) and a 9.5% quantum yield. By highlighting intersystem crossing mechanisms via computational methods, the work provides a blueprint for next-generation photonic and encryption applications.

The work finds synergy with a broader review on halide perovskites (Contribution 2 [7]), which explores biomedical prospects through coated nanocrystals with enhanced biocompatibility and reduced toxicity. As both structural tunability and stability issues are addressed through innovative encapsulation strategies, the biomedical field is poised to benefit from these optoelectronic breakthroughs.

3. Semiconductors in Environmental Remediation and Energy

In the realm of environmental catalysis, photocatalysts incorporating biogenic materials and nanostructures stand out. A TiO₂-cuttlebone composite (Contribution 3 [8]) exhibited high solar-driven activity for tetracycline hydrochloride degradation, aided by the formation of carbonate radicals and a recyclability-focused 3D-printed photocatalytic device. Furthermore, the broccoli-like Ag/Cu₂O/ZnO nanowire heterostructure [9] (Contribution 4 [10]) effectively degrades methyl orange under visible light, driven by plasmon-enhanced charge separation and p–n heterojunctions [11].

These studies underscore a clear trend: the hybridization of inorganic semiconductors with morphological or biological motifs can significantly enhance photocatalytic activity, opening doors to green chemistry and energy applications.

4. Tailoring Magnetic and Electronic Properties for Spintronics

The study by Liu et al. (Contribution 5 [12]) exemplifies the theoretical exploration of spintronic materials. By intercalating 3d transition metals [13] into bilayer TMDs, a wide spectrum of magnetic phases—ranging from half-metals to ferromagnetic semiconductors—was uncovered via density functional theory. These materials, particularly V- and Cr-doped MoS₂ and VS₂, offer promising platforms for spin-filtering and magnetic logic devices.

CrN nanoparticles (Contribution 6 [14]) are also revisited in a thorough review focusing on correlated electronic and structural phase transitions [15]. By dissecting synthesis-dependent variability, the review establishes CrN as an excellent system for probing fundamental spin–lattice interactions and phase coupling phenomena. These insights can inform the design of robust multifunctional devices.

5. Functional Oxides and Thin Film Technologies

The use of NiO_x as a p-type semiconductor [16] in heterojunction photodiodes is elegantly explored in a practical device study (Contribution 7 [17]). The work highlights how deposition temperature and post-annealing influence responsivity and power efficiency. Notably, rapid thermal annealing substantially enhances photoresponse but introduces voltage memory effects, offering critical insight for sensor design.

Complementing this is the review on AlN thin films (Contribution 8 [18]), which chronicles advances in magnetron sputtering techniques. By discussing the interplay between sputtering parameters and film quality, the review underscores AlN’s emerging importance in radio frequency and thermal management applications. Both papers reinforce the growing relevance of transition metal oxides [19] and nitrides in thin-film electronics.

6. Composite and Hybrid Semiconductor Systems

Hybrid systems often combine the best of inorganic and organic properties. A study on polysilane–barium titanate composites (Contribution 9 [20]) demonstrates how ultrasonication [21] can yield a ultraviolet-stable, semiconducting material with enhanced dielectric properties. The resulting composite exhibits promising electromagnetic shielding characteristics and improved conductivity, suggesting applications in electronics exposed to high-radiation or harsh environments.

The coupling of dielectric and semiconducting properties in such hybrid systems is increasingly vital, especially for applications in smart electronics and multifunctional materials. These approaches illustrate how a careful matrix-filler design can push materials performance beyond classical boundaries.

7. Crystallization and Dimensionality Control

The fabrication of single crystals is critical to achieving predictable and reproducible properties. The Bridgman method, comprehensively reviewed in Contribution 10 [22], has re-emerged as a powerful tool for growing high-quality metal halide single crystals. This review outlines the evolution of dimensional control (zero-dimensional to 3D) in halide structures, emphasizing crystal purity and application-specific tailoring. The method’s resurgence stems from its capacity to overcome the limitations of solvent-based techniques, ensuring scalability and performance uniformity.

Alongside the 2D phosphorescent perovskites [23] in Contribution 1 [6], this review further validates the significance of dimensionality in tuning optical and electronic responses.

8. Perovskites at the Forefront

Three of the eleven papers (Contributions 1 [6], 2 [7], and 11 [24]) focus on perovskites [25], affirming their central role in this field. The comprehensive review by Tayari et al. (Contribution 11 [24]) discusses perovskite structure–property relationships and the roles of polarization, charge transport, and magnetic interactions. It ties together fundamental insights with device-level challenges such as scalability and environmental resilience. These reviews, in conjunction with focused studies on optical RTP performance and biocompatibility, position perovskites as true multifunctional materials with strong potential across sectors.

9. Conclusion: Toward a Unified Future in Inorganic Semiconductors

This second edition of “Advanced Inorganic Semiconductor Materials” reveals a dynamic and rapidly diversifying field. We see the merging of computational design, environmentally inspired synthesis, device engineering, and high-throughput fabrication. The 11 papers collected here capture a thematic convergence around tunability, dimensional control, hybrid functionality, and application-focused optimization.

From RTP-enabled cryptography (Contribution 1 [6]), to solar-assisted water purification (Contribution 3 [8]), and spintronic platforms via intercalated TMDs (Contribution 5 [12]), these contributions provide a glimpse into the future of electronics, energy, and biomedical technologies [26]. While challenges remain—particularly in stability, integration, and scalability—this volume affirms that the pursuit of tailored functionality in inorganic semiconductors is not only fruitful but essential.

This edition will stimulate continued interdisciplinary collaboration [27], inspiring both curiosity and application-driven exploration in materials science, which we sincerely hope will contribute to the next edition of this SI “Advanced Inorganic Semiconductor Materials: 3rd Edition” [28].