BaZrS3 is a prototypical chalcogenide perovskite, an emerging class of unconventional semiconductor. Recent results on powder samples reveal that it is a material with a direct band gap of 1.7-1.8 eV, a very strong light-matter interaction, and a high chemical stability. Due to the lack of quality thin films, however, many fundamental properties of chalcogenide perovskites remain unknown, hindering their applications in optoelectronics. Here we report the fabrication of BaZrS3 thin films, by sulfurization of oxide films deposited by pulsed laser deposition. We show that these films are n-type with carrier densities in the range of 10 19 -10 20 cm -3 . Depending on the processing temperature, the Hall mobility ranges from 2.1 to 13.7 cm 2 /Vs. The absorption coefficient is > 10 5 cm -1 at photon energy > 1.97 eV. Temperature dependent conductivity measurements suggest shallow donor levels. By assuring that BaZrS3 is a promising candidate, these results potentially unleash the family of chalcogenide perovskites for optoelectronics such as photodetectors, photovoltaics, and light emitting diodes.

The design of optoelectronic devices fabricated from III-nitride materials is aided by knowledge of the refractive index and absorption coefficient of these materials. The optical properties of GaN, AlN and AlGaN grown by MOVPE on sapphire substrates were investigated by means of transmittance and reflectance measurements. Thin (less than 0.5 μm) single crystal films were employed to insure that transmission measurements could be obtained well above the optical band gap. The influence of alloy broadening on the absorption edge was investigated by using a series of AlGaN alloy samples with a range of Al compositions. The optical absorption coefficient above the band gap was obtained for AlGaN having up to 38% Al composition. The refractive index below the band gap was determined for the same series of samples. These properties provide information critical to the optimal design of solar blind detectors or other optoelectronic devices.

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The paper presents a piezoresistive absolute micro pressure sensor, which is of great benefits for altitude location. In this investigation, the design, fabrication, and test of the sensor are involved. By analyzing the stress distribution of sensitive elements using finite element method, a novel structure through the introduction of sensitive beams into traditional bossed diaphragm is built up. The proposed configuration presents its advantages in terms of high sensitivity and high overload resistance compared with the conventional bossed diaphragm and flat diaphragm structures. Curve fittings of surface stress and deflection based on ANSYS simulation results are performed to establish the equations about the sensor. Nonlinear optimization by MATLAB is carried out to determine the structure dimensions. The output signals in both static and dynamic environments are evaluated. Silicon bulk micromachining technology is utilized to fabricate the sensor prototype, and the fabrication process is discussed. Experimental results demonstrate the sensor features a high sensitivity of 11.098 μV/V/Pa in the operating range of 500 Pa at room temperature, and a high overload resistance of 200 times overpressure to promise its survival under atmosphere. Due to the excellent performance above, the sensor can be applied in measuring the absolute micro pressure lower than 500 Pa.

By introducing stretchability and/or deformability to planar electronics, devices can conformably attach to 3D curved surfaces with minimal invasiveness, which is of great interest for next‐generation wearables in clinical and biological applications. Here, a feasible route is demonstrated to generate deformable 3D structures as a robust platform to construct electronic systems by utilizing silver nanowires/parylene hybrid films in a way analogous to the art of kirigami. The hybrid films exhibit outstanding electrical conductivity along with decent optical transparency, flexibility, and long‐term stability. These merits enable these films to work as electrodes for electrocardiogram recording with comparable accuracy to a commercial counterpart, and to fabricate a 7‐GHz monopole antenna with good omni‐directionality and a peak gain of 1.35 dBi. More importantly, a general scheme for constructing 3D deformable electronic systems is presented, including unique patterning procedures and rational cut designs inspired by kirigami. As an example, deformable transparent humidity sensors are fabricated to work on elbows and finger joints for sweating monitoring. The strategy demonstrated here for 3D deformable system construction is versatile and holds great promise for future advanced health monitoring at diverse and complex epidermal surfaces.