AlGaN/GaN HEMTs with several different designs of field plate structure are studied for device optimization purposes. To increase device breakdown voltage, optimal dimensions of field plates were first investigated using Silvaco TCAD software, and the electrical characteristics of the devices are analyzed. Several devices were designed and fabricated based on the simulation results. It has been confirmed that the gate-source composite field plate (SG-FP) has a higher breakdown voltage than other types of field plate structures, with FOM reaches 504 MW/cm⁻², showing that the device with SG-FP structure outperforms the other three structures. The experiment and simulation verify that the gate-source composite field plate optimizes FOM by increasing the breakdown voltage and reducing the intrinsic on-resistance so that the device has better electrical performance and a wider application range.

A color-modulating optical coating display based on phase change materials (PCM) and indium tin oxide (ITO) is fabricated and analyzed. We demonstrate that altering the thickness of top-ITO in this PCM-based display device can effectively change color. The significant role of the top-ITO layer in the thin-film interference in this multilayer system is confirmed by experiment as well as simulation. The ternary-color modulation of devices with only 5 nano thin layer of phase change material is achieved. Furthermore, simulation work demonstrates that a stirringly broader color gamut can be obtained by introducing the control of the top-ITO thickness.

A multi-color solid-state display structure has been fabricated and characterized, which is based on phase-change material Ge₂Sb₂Te₅ (GST) and conducting transparent material indium tin oxide (ITO). The significant influence of ITO is investigated by experiments as well as simulations. We found that the ITO layer in fact plays a significant or even a dominate role in the color change of GST-based multi-layer solid state display structure. Multi-color modulation can be achieved by changing the phase state of both ITO and GST. Based on those results, better color presentation can be realized by improving the design of this new solid-state display.