In this work, the impact of nitrogen doping (N-doping) on the distribution of sub-gap states in amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) is qualitatively analyzed by technology computer-aided design (TCAD) simulation. According to the experimental characteristics, the numerical simulation results reveal that the interface trap states, bulk tail states, and deep-level sub-gap defect states originating from oxygen-vacancy- (V_o) related defects can be suppressed by an appropriate amount of N dopant. Correspondingly, the electrical properties and reliability of the a-IGZO TFTs are dramatically enhanced. In contrast, it is observed that the interfacial and deep-level sub-gap defects are increased when the a-IGZO TFT is doped with excess nitrogen, which results in the degeneration of the device’s performance and reliability. Moreover, it is found that tail-distributed acceptor-like N-related defects have been induced by excess N-doping, which is supported by the additional subthreshold slope degradation in the a-IGZO TFT.

In recent years, solar-blind ultraviolet photodetectors (PDs) based on β-Ga2O3 have gained significant attention for their applications in military and commercial fields. This study explores the grain orientation and crystal quality of Ga2O3 films grown on sapphire substrates via RF magnetron sputtering at various growth temperatures and post-annealing temperatures. After determining optimal temperatures, we investigated the photoelectric performance of the metal/semiconductor/metal detectors with different oxygen flow ratios (0%, 5%, 10%). The PD grown in a pure Ar atmosphere exhibited the highest responsivity (48.93 A/W), remarkable detectivity (1.35 × 1014 Jones), excellent external quantum efficiency (2.39 × 104%), and also rapid photoresponse time (0.118 s rise time/0.031 s decay time) under 1000 μW/cm2 254 nm light illumination. These results are attributed to the internal gain from an optimal concentration of oxygen vacancies in the well-crystallized film, without the deep-level defects typically induced under oxygen-rich conditions. Leveraging this optimized chip, we developed a deep ultraviolet communication system using a Ga2O3-based detector. The system achieved a data rate of 65 kbps with a pseudo-random binary sequence signals utilizing on-off keying. Additionally, using discrete multi-tone signals modulated with 32-quadrature amplitude modulation, it reached a maximum data rate of 80.65 kbps, both satisfying forward error correction threshold of 3.8 × 10−3. These results highlight the considerable potential of high-quality β-Ga2O3 solar-blind PDs for ultraviolet communication applications.

Micro-LED arrays exhibit high brightness, a long lifespan, low power consumption, and a fast response speed. In this paper, we have proposed a series-biased micro-LED array by using a nitride layer with multi-quantum wells epitaxial on sapphire substrate. The III-nitride multiple quantum wells serving as the micro-LED active material enable both luminescence and detection functionalities. The micro-LED array combines lighting, detection, and communication capabilities. We have conducted a thorough analysis of the micro-LED array’s optoelectronic features in both lighting and detection modes. We also explore visible light communication performance across different arrangements of single micro-LED devices within the series-biased array. Our research achieves 720p video transmission via visible light communication using the micro-LED array, supporting a communication rate of up to 10 Mbps. Our contributions encompass the successful integration of lighting and detection functions and a comprehensive assessment of optoelectronic and communication performance. This study highlights the multifunctional micro-LED array’s potential as a transceiver terminal in visible light communication systems, expanding its applications from smart lighting to visible light communication and photonic integrated chips. These innovations enhance our understanding of micro-LED technology and its versatile applications.

Inserting multiple quantum wells (MQWs) into a p–n junction, III-nitride MQW diodes can separately function as a light transmitter, modulator, and receiver under different bias conditions. Owing to the spectral overlap between the emission and responsivity spectra, the emitted light from the transmitter is able to be modulated and detected by the modulator and receiver, which have identical MQW structures. Here, we develop a compatible fabrication process to monolithically integrate an III-nitride light transmitter, waveguides, Y-splitter, modulators, Y-combiner, and receiver into a tiny chip. An on-chip 405 nm light communication system is established and exhibits a transmission rate of 260 Mbps in the non-return-to-zero on-off keying scheme. The results pave a feasible route to develop sophisticated monolithic photonic circuit on an III-nitride-on-silicon platform.