Electrical and structural properties of GaN films and GaN/InGaN light-emitting diodes grown on porous GaN templates fabricated by combined electrochemical and photoelectrochemical etching

Light-output enhancement of InGaN light emitting diodes regrown on nanoporous distributed Bragg reflector substrates

“…The change in the position of the efficiency peak could be an indication of modification of the electric fields across the QWs due to the presence of the porous layer, leading to shorter carrier lifetimes 26,27) . Such modification has been suggested to explain enhanced cathodoluminescence signals from LED structures overgrown on thick layers of porous GaN, where it was thought to be related to strain relief in the QWs 23) ; strain relief will tend to lower the piezoelectric fields present across the heterostructure. Such a strain-relief effect has also been suggested to cause a blue-shift in the emission from LEDs on NP-DBRs compared to nonporous samples 18) .…”

III‐Nitride Nanowires as Building Blocks for Advanced Light Emitting Diodes

“…Approaches in separation and transfer, again, are similar to the ones developed for top‐down microLEDs and bottom‐up NW LEDs. One final thing to be mentioned here is that the top‐down NW LEDs seem to be particularly amenable to the new separation technology developed for MOCVD grown planar LEDs in our earlier papers . In this technology a combination of electrochemical etching (ECE) and photoelectrochemical etching (PECE) of undoped GaN/n + ‐GaN is applied to fabricate porous templates schematically displayed in Figure .…”

“…These ECE‐PECE templates are then used to grow the standard LED structures that can be easily separated from the substrate by mechanical peeling off using the weak places presented by the ECE‐PECE template as breaking points. The advantages of LED structures thus prepared are related to lower strain and lower density of structural defects, such as V‐pits . This technique can come very handy when organizing the efficient separation and transfer of the NW LEDs prepared by the top‐down approach described above.…”

Threading dislocation annihilation in the GaN layer on cone patterned sapphire substrate

“…In order to solve this problem, the mask-free patterned substrate (PSS) technology becomes very popular for high-efficiency InGaN/GaN-based LEDs of commercial production and institute research [6,7]. However, most of the studies related to PSS have focused on evaluating the device's capability, in-depth understanding the mechanism of the annihilation of TDs and compared with the traditional ELOG was lack in the literature [8,9].…”

“…In order to solve this problem, the mask-free patterned substrate (PSS) technology becomes very popular for high-efficiency InGaN/GaN-based LEDs of commercial production and institute research [6,7]. However, most of the studies related to PSS have focused on evaluating the device's capability, in-depth understanding the mechanism of the annihilation of TDs and compared with the traditional ELOG was lack in the literature [8,9].This study investigates the distribution and the annihilation mechanism of defects in GaN film grown on cone shape patterned sapphire substrates using a high-resolution X-ray diffraction (HRXRD), scanning electron microscope (SEM), transmission electron microscope (TEM), atomic force microscopy (AFM). The mechanism of TDs reduction due to the TDs bending toward cone substrates was revealed.…”