Effect of thermal annealing induced by p-type layer growth on blue and green LED performance

Internal quantum efficiency improvement of InGaN/GaN multiple quantum well green light-emitting diodes

“…It's promising to reduce the growth temperature of a p−GaN layer for better optical and structural properties of InGaN/GaN MQW [21]. The quality of InGaN/GaN MQW green LED could also be improved by "active−re− gion−friendly" p−InGaN layers grown at low temperature [22][23][24]. Figures 5(a)-5(d) show that structural of MQWs with a p−GaN layer grown at different temperature.…”

“…Taeil Jung et al demonstrated a semipolar green InGaN/GaN MQW fabricated on low cost c−plane sapphire substrates and achieved 30% higher inter− nal quantum efficiency than a conventional c−plane MQW [37]. In addition, bulk−GaN substrates with arbitrary orien− tations are attractive to grow a nonpolar and semipolar green LED such as (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) orientation GaN [38,39], (20)(21) semipolar GaN [40,41], and a−plane GaN [42].…”

Novel Approaches to High-Efficiency III-V Nitride Heterostructure Emitters for Next-Generation Lighting Applications

“…For p-type InGaN, it is well known that hole concentration can be enhanced as a consequence of reduced activation energy of Mg acceptor in In x Ga 1-x N with increasing indium composition, x In 11,12,13 . In this study, sample (a), which is In 0.04 Ga 0.96 N:Mg grown at 840°C, shows low resistivity with higher hole concentration (p=2.0×10 18 cm -3 and a low resistivity of 0.5 Ω-cm) due to the reduced Mg activation energy, as shown in Figure 3. The sample (a), however, shows lower carrier mobility (µ h~6 cm 2 /V·s) due to less-perfect crystalline quality relative to sample (b) or (c).…”

“…Figure 3 shows the measured hole concentration, mobility, and resistivity of the samples (a), (b), and (c). A high free-hole concentration of p=1.6×10 18 cm -3 and a mobility of µ h~1 2 cm 2 /V·s, resulting in a very low resistivity of 0.33 Ω-cm at 300 K for the GaN:Mg sample (c), which was grown under optimized growth condition at 1040°C, were achieved. As shown in Figure 5, secondary ion mass spectroscopy (SIMS) depth profiling for the sample reveals that carbon and oxygen impurity levels are well controlled -very low near detection limit.…”

“…Intentional doping in the quantum well (QW) and/or QWB has been reported to modify the electron and hole carrier confinement, and in order to improve the + electron injection layer. GaN used in the QWB has different Si doping levels to study the effect on electrical and optical properties of LEDs: For the Si doping in the QWB, 0 sccm (unintentionally doped), 4 sccm, and 8 sccm of SiH 4 (10 ppm balanced in H 2 ) were used and they are estimated to have free electron concentrations of the order of 10 16 , 1×10 18 , and 5×10 18 cm -3 , respectively. The epitaxial structures were fabricated in the standard mesa-type devices.…”