Influence of Mg Doping on the Morphological, Optical, and Structural Properties of InGaN/GaN Multiple Quantum Wells

Abstract

In this report, the influence of magnesium doping on the characteristics of InGaN/GaN multiple quantum wells (MQWs) was investigated by means of atomic force microscopy (AFM), photoluminescence (PL), and X-ray diffraction (XRD). Five-period InGaN/GaN MQWs with different magnesium doping levels were grown by metalorganic chemical vapor deposition. The AFM measurements indicated that magnesium doping led to a smoother surface morphology. The V-defect density was observed to decrease with increasing magnesium doping concentration from $10 9 cm -2 (no doping) to $10 6 cm -2 (Cp 2 Mg: 0.04 sccm) and further to 0 (Cp 2 Mg: 0.2 sccm). The PL measurements showed that magnesium doping resulted in stronger emission, which can be attributed to the screening of the polarization-induced band bending. XRD revealed that magnesium doping had no measurable effect on the indium composition and growth rate of the MQWs. These results suggest that magnesium doping in MQWs might improve the optical properties of GaN photonic devices.

Impact of thermal treatment on the optical performance of InGaN/GaN light emitting diodes

“…However, the intensity increase detected on the annealed samples (Figure 1(a)) cannot be simply explained by the diffusion of Mg towards the quantum well/barrier system, since -if this were the case -the intensity increase should be accompanied by a blue-shift of the emission peak, as explained in Ref. 13, and this is not observed (see Figure 1(a)). A further confirmation of this hypothesis is given by the fact that the efficiency increase does not involve only the active layer, but also the GaN near band edge emission (Figure 1), which is likely to originate from the top p-GaN layer, rather than from the barriers.…”

“…13). However, the intensity increase detected on the annealed samples (Figure 1(a)) cannot be simply explained by the diffusion of Mg towards the quantum well/barrier system, since -if this were the case -the intensity increase should be accompanied by a blue-shift of the emission peak, as explained in Ref.…”

The influence of MOVPE growth conditions on the shell of core-shell GaN microrod structures

“…Beaumont et al report the suppression of r-plane pyramidal growth and the development of homogeneous c-plane platelets for the growth of p-doped GaN on a patterned SiN/GaN/sapphire template [23]. A reduction in V-Pit density in p-doped GaN layers is reported by Chen et al [24], which is also attributed to the increased lateral growth on pdoped GaN. A smoothing effect of magnesium has also been noticed in the MBE growth of GaN [25] and was attributed to a surfactant effect due to the lowering of surface diffusion barriers by an electron counting mechanism.…”

Effect of Mg doping in the barrier of InGaN/GaN multiple quantum well on optical power of light-emitting diodes

“…Recently, the Mg doping of an InGaN well layer was reported to significantly reduce the V-defect density in the MQW and to enhance PL intensity. 6 When LEDs are used for a high power application, the injection current is increased and hole injection becomes increasingly important. However, hole injection to a MQW is limited due to the heavy effective mass of a hole and to the relatively low hole concentration in p-GaN.…”