Effect of Si doping in wells of AlGaN/GaN superlattice on the characteristics of epitaxial layer

Abstract

An AlGaN/GaN superlattice grown on the top of a GaN buffer induces the broadening of the full width at half maximum of ( 102) and (002) X-ray diffraction rocking curves. With an increase in the Si-doped concentration in the GaN wells, the full width at half maximum of the (102) rocking curves decreases, while that of the (002) rocking curves increases. A significant increase of the full width at the half maximum of the (002) rocking curves when the doping concentration reaches 2.5 × 10 19 cm −3 indicates the substantial increase of the inclined threading dislocation. High level doping in the AlGaN/GaN superlattice can greatly reduce the biaxial stress and optimize the surface roughness of the structures grown on the top of it.

Efficiency droop in InGaN/GaN-based LEDs with a gradually varying In composition in each InGaN well layer

“…2 and 3 show that the SA should have sharper interfaces and better crystal quality than SB. [20][21][22] Furthermore, based on the aforementioned HRXRD data, such as the intensity ratio of the negative MQW satellite peaks to their positive counterparts-related to the ratio of the layer thickness values, the angular position of the MQW peak, and the angular distance between adjacent satellite peaks, both the thickness (well thickness plus barrier thickness) of one period of MQW and the In mole fraction in the WL can be estimated. [23][24][25] The thickness values of both samples are estimated to be ca.…”

GaN hexagonal pyramids formed by a photo-assisted chemical etching method

“…[1] However, the total light output from these LEDs is still rather low. [2,3] Enhancing the efficiency of GaN-based LEDs is an area of active study. [4] There are two principal approaches for improving LED efficiency: the first is increasing the internal quantum efficiency, which is determined by the crystal quality and epitaxial layer structure, and the second is increasing the light extraction efficiency, which is primarily limited by the total internal reflection of the light generated from the active region at the semiconductor-air interface.…”

Light-extraction efficiency and forward voltage in GaN-based light-emitting diodes with different patterns of V-shaped pits

“…Despite the recent achievements -the internal quantum efficiency (IQE) of LEDs is now up to 80% -the light-extraction efficiency (LEE), which is only 26% for a planar GaN LED, still needs to be enhanced. [1][2][3] A major factor responsible for the poor light-extraction efficiency is the total internal reflection (TIR) when the angle of incidence exceeds the critical angle θ c determined by Snell's law. This is connected with the refractive index, which for GaN is 2.5 at 460 nm, whereas that of air is 1.0.…”