Morphologies and optical and electrical properties of InGaN/GaN micro-square array light-emitting diode chips

Abstract

InGaN/GaN micro-square array light-emitting diode (LED) chips (micro-chips) have been prepared via the focused ion beam (FIB) etching technique, which can not only reduce ohmic contact degradation but also control the aspect ratio precisely in three-dimensional (3D) structure LED (3D-LED) device fabrication. The effects of FIB beam current and micro-square array depth on morphologies and optical and electrical properties of the micro-chips have been studied. Our results show that sidewall surface morphology and optical and electrical properties of the micro-chips degrade with increased beam current. After potassium hydroxide etching with different times, an optimal current-voltage and luminescence performance can be obtained. Combining the results of cathodoluminescence mappings and light output-current characteristics, the light extraction efficiency of the micro-chips is reduced as FIB etch depth increases. The mechanisms of micro-square depth on light extraction have been revealed by 3D finite difference time domain.

Design and Analysis of Blue InGaN/GaN Plasmonic LED for High-Speed, High-Efficiency Optical Communications

“…We observe that, for the patterned areas, another source of quenching is the surface damage caused by FIB milling. The kinetic energy transfer from the Ga + ions to the LED crystal lattice generates a thin (few nm) damaged amorphous layer on the etched surface, which can be removed by post-FIB wet etching in a heated KOH solution. − …”

Time–Energy Quantum Uncertainty: Quantifying the Effectiveness of Surface Defect Passivation Protocols for Low-Dimensional Semiconductors

“…Owing to the higher surface-area-to-volume ratios in lower-dimensional semiconductor structures and the subsequent induction of forbidden energy-band transitions caused by surface trap states, 13 14 and is commonly used in semiconductor chip fabrication. 15,16 Yet, the aforementioned reports lack discussions of physical insights into the extent of the goodness of nanowire surface passivation through quantum mechanical descriptions and criteria that set theoretical bounds. Such theoretical bounds provide a fundamental scale of descriptions that dene relevant and universal gures of merit to assess the eectiveness of passivation protocols.…”

“…The coating was a result of severe polymeric deposition because of the long carbon chain in 1-octadecanethiol. Comparatively, 1,2-ethanedithiol (EDT, HSCH 2 CH 2 SH), having a much shorter carbon chain, can mitigate the polymeric deposition and thus preserve the integrity of the nanowires. , Whereas 1-octadecanethiol and 1,2-ethanedithiol are organic chemical compounds, potassium hydroxide (KOH) is an elementary and nontoxic inorganic compound that was previously used to suppress surface recombination in AlGaN nanowires and is commonly used in semiconductor chip fabrication. , Yet, the aforementioned reports lack discussions of physical insights into the extent of the goodness of nanowire surface passivation through quantum mechanical descriptions and criteria that set theoretical bounds. Such theoretical bounds provide a fundamental scale of descriptions that define relevant and universal figures of merit to assess the effectiveness of passivation protocols.…”