The epitaxial growth of technically-important β-Ga2O3 semiconductor thin films have not been realized on flexible substrates due to limitations by the high-temperature crystallization conditions and the lattice-matching requirements. In this report, for the first time single crystal β-Ga2O3 (-201) thin films is epitaxially grown on the flexible CeO2 (001)-buffered hastelloy tape. The results indicate that CeO2 (001) has a small bi-axial lattice mismatch with β-Ga2O3 (-201), thus inducing a simultaneous double-domain epitaxial growth. Flexible photodetectors are fabricated based on the epitaxial β-Ga2O3 coated tapes. Measurements show that the obtained photodetectors have a responsivity of 40 mA/W, with an on/off ratio reaching 1000 under 250 nm incident light and 5 V bias voltage. Such photoelectrical performance is already within the mainstream level of the β-Ga2O3 based photodetectors by using the conventional rigid single crystal substrates; and more importantly remained robust against more than 1000 cycles of bending tests. In addition, the epitaxy technique described in the report also paves the way for the fabrication of a wide range of flexible epitaxial film devices that utilize the materials with lattice parameters similar to β-Ga2O3, including GaN, AlN and SiC.

Arrays of ordered nanorods are of special interest in many fields. However, it remains challenging to obtain such arrays on conducting substrates in a facile manner. In this article, we report the fabrication of highly ordered and vertically standing nanorod arrays of both metals and semiconductors on Au films and indium tin oxide glass substrates without an additional layering. In this approach, following the simple hydrophilic treatment of an anodic aluminum oxide (AAO) membrane and conducting substrates, the AAO membrane was transferred onto the modified substrates with excellent adhesion. Subsequently, nanorod arrays of various materials were electrodeposited on the conducting substrates directly. This method avoids any expensive and tedious lithographic and ion milling process, which provides a simple yet robust route to the fabrication of arrays of 1D materials with high aspect ratio on conducting substrates, which shall pave the way for many practical applications in a range of fields.

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Gate controllability is a key factor that determines the performance of GaN high electron mobility transistors (HEMTs). However, at the traditional metal‐GaN interface, direct chemical interaction between metal and GaN can result in fixed charges and traps, which can significantly deteriorate the gate controllability. In this study, Ti3C2Tx MXene films are integrated into GaN HEMTs as the gate contact, wherein van der Waals heterojunctions are formed between MXene films and GaN without direct chemical bonding. The GaN HEMTs with enhanced gate controllability exhibit an extremely low off‐state current (IOFF) of 10−7 mA mm−1, a record high ION/IOFF current ratio of ≈1013 (which is six orders of magnitude higher than conventional Ni/Au contact), a high off‐state drain breakdown voltage of 1085 V, and a near‐ideal subthreshold swing of 61 mV dec−1. This work shows the great potential of MXene films as gate electrodes in wide‐bandgap semiconductor devices.

The polarization-induced electric field in the IIInitride UV light-emitting diode (LED) allows for significant flexibility in device design to address the electron overflow and hole injection issues. The conventional AlGaN-based UV LED with the PIN structure suffers from insufficient carriers especially hole concentration due to the large valence band barrier for hole injection and p-type doping challenge. Our systematic study reveals that the inverse design of the n-type and p-type layer shall build an opposite polarization-induced field to suppress electron overflow as well as simultaneously enhance hole injection. To design this p-side down UV LED and improve the hole injection, we adopt the n-AlGaN/i-InGaN/p-AlGaN buried tunneling junction (BTJ) instead of the bottom p-layer. The tunneling probability and output power of the LED are further investigated by optimizing the composition and thickness of the InGaN layer. Simulation results show that the optimized 3 nm In0.3Ga0.7N tunneling layer could lead to several orders of magnitude enhancement for LED output power. This study is significant for the pursuit of highly efficient UV LEDs.

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With deepening internationalization, English has become an increasingly important communication tool. Because traditional English teaching has short teacher-student interaction time, lack of oral English training environment, and single learning method, the oral English teaching is not ideal, and the students’ “speaking” confidence is insufficient. Aimed at addressing the exposed problems of traditional English reading teaching, this paper proposes a multimedia-based English reading teaching mode. On this basis, establish a voice recognition phoneme network grid to detect the recognition results. Secondly, the lattice is used to generate the confusion network mesh, and the acoustic posterior probability is calculated. Then, the feature vector is input into the SVM classifier for confidence mark, and finally the feature is extracted by principal component analysis. The research shows that multimedia network teaching can teach more vividly, increasing the initiative of students. At the same time, it is shown that the speech recognition confidence learning algorithm can improve the language learning system.