The increasing security threat is a serious challenge to the internet of things (IoT). Hardware‐based security primitive is an essential and powerful way to protect IoT devices from various attacks. But most of the current security hardwares are based on macrophysical features, which are usually produced by reproducible deterministic processes and can be copied by counterfeiters. Herein, a physical unclonable function (PUF) with high robustness based on the intrinsic random micro‐/nanostructures of the electronic packages is proposed thereby demonstrating a low‐cost and label‐free hardware security solution for IoT. Using the unique surface micropattern and the spatially coded laser scattering, the proposed PUFs can be used as anticounterfeiting labels, authentication tokens and cryptographic key generators. With the help of the proposed PUFs, the safety protection is still effective even when the attacker is able to get access to the database because the secret keys are inherently hidden in the complex microscopic stochastic physical features of the PUFs but not the database. The proposed package‐enabled PUFs provide a promising and practical physical protection solution for IoT security.

Point defects in wide bandgap III-nitride semiconductors have been recently reported to be one kind of the most promising near-infrared (NIR) quantum emitters operating at room temperature (RT). But the identification of the point defect species and the energy level structures as well as the transition dynamics remain unclear. Here, the photophysical properties of single-photon emission from point defects in AlGaN films are investigated in detail. According to the first-principles calculations, a three-level model was established to explain the transition dynamics of the quantum emitters. An anti-site nitrogen vacancy complex (V_NN_Ga) was demonstrated to be the most likely origin of the measured emitter since the calculated zero-phonon line (ZPL) and the lifetime of V_NN_Ga in the AlGaN film coincide well with the experimental results. Our results provide new insights into the optical properties and energy level structures of quantum emission from point defects in AlGaN films at RT and establish the foundation for future AlGaN-based on-chip quantum technologies.

Point defect-based single-photon emitters (SPEs) in GaN have aroused a great deal of interest due to their room-temperature operation, narrow line width and high emission rate. The room-temperature SPEs at the telecommunication bands have also been realized recently by localized defects in GaN in experiments, which are highly desired for the practical applications of SPEs in quantum communication with fiber compatibility. However, the origin and underlying mechanism of the SPEs remain unclear to date. Herein, our first-principle calculations predict and identify an intrinsic point defect N_Ga in GaN that owns a zero-phonon line (ZPL) at telecommunication windows. By tuning the triaxial compressive strain of the crystal structure, the ZPL of N_Ga can be modulated from 0.849 eV to 0.984 eV, covering the fiber telecommunication windows from the O band to the E band. Besides the ZPL, the formation energy, band structure, transition process and lifetime of the SPEs under different strains are investigated systematically. Our work gives insight into the emission mechanism of the defect SPEs in GaN and also provides effective guidance for achieving wavelength-tunable SPEs working in fiber telecommunication windows.

Defect single-photon emitters (SPE) in gallium nitride (GaN) have garnered great attentions in recent years due to the advantages they offer, including the ability to operate at room temperature, narrow emission linewidths, and high brightness. Nevertheless, the precise nature of the single-photon emission mechanism remains uncertain due to the multitude of potential defects that can form in GaN. In this work, our systematical investigation with the ab initio calculation indicates that carbon and silicon, as common dopants in gallium nitride, can interact with intrinsic defects in GaN and form new high-speed defect single-photon sources. Our findings identify a ternary defect N_GaV_NC_N that possesses a short lifetime of less than 1 ns and a small zero-photon line (ZPL) of 864 nm. In other words, this defect can serve as a high-speed single photon source in the short wavelength window for fiber communication. In sharp contrast, the Si-supported defect N_GaV_NSi_N has a higher unoccupied defect energy level which enters the conduction band and is therefore unsuitable for single photon emission. A systematic investigation has been conducted into the potential defects, thermal stability, and single-photon emission properties. The relaxation calculation and self-consistent calculations employed the Perdew–Burke–Ernzerhof exchange-correlation functional and Heyd–Scuseria–Ernzerhof exchange-correlation functional, respectively. These findings indicate the potential for high-performance single-photon sources through carbon or silicon doping of GaN.