Studies of InGaN∕GaN multiquantum-well green-light-emitting diodes grown by metalorganic chemical vapor deposition

Abstract

InGaN ( 3 nm ) ∕ GaN ( 5 nm ) three period multiquantum green-light-emitting diodes (LEDs) grown by the metalorganic chemical vapor deposition technique have been studied using high-resolution transmission electron microscopy (HRTEM), double crystal high resolution x-ray diffraction (HRXRD) and low temperature photoluminescence. HRTEM analysis showed that the defect density gradually decreased in the growth direction with increasing thickness. Self-assembled quantum dot-like structures in the wells and black lumps between the well and barrier due to In segregation and strain contrast were observed, respectively. The HRXRD spectrum of the green LED structure was simulated using the kinematical theory method to obtain the composition and thickness of the well and barrier. The quantum-well (QW) green emission peak 2.557eV at 10K showed “S” shaped shift like a red–blue–red shift with variation of the temperature in the photoluminescence spectra due to potential fluctuations caused by inhomogeneous alloy distribution in the wells. The activation energy of 49meV obtained from the QW green emission line indicated deepening of the localization of the carriers.

Enabling High-Injection Current Light-Emitting Diodes Prepared on 10-$\mu \text{m}$ -Thick GaN Films Grown by Hydride Vapor Phase Epitaxy

“…The activation energy of the LEDs could thus be deduced from the slope of the data in the temperature range of 140-300 K from Fig. 6 [20]. The activation energy values of LED-R, LED-1, and LED-2 were approximately 44, 59, and 48 meV, respectively.…”

Metalorganic chemical vapor deposition and structural/optical characteristics of InGaN/GaN multiple quantum wells grown on sapphire for light emitting diode application

“…9. This large value of E A (80 meV) indicates the localization of the carriers in the structure [25]. Assuming that the internal quantum efficiency equals unity at 9 K, we obtained the internal quantum efficiency as high as 34.8%…”

“…InGaN/GaN heterostructures can exhibit intense photoluminescence (PL) and electroluminescence (EL) despite of a high dislocation and defects density existed [10,11], and have advantages, such as, lowering the threshold current density for LDs and reducing the device sensitivity to temperature [12,13]. More research efforts have been made on InGaN/GaN multiple quantum wells [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30], among which, most of InGaN/GaN MQWs were prepared by the metalorganic chemical vapor deposition (MOCVD) technique, that has been approved a powerful technology for R&D and industry production of III-nitride materials and devices.…”

Morphology evolution and emission properties of InGaN/GaN multiple quantum wells grown on GaN microfacets using crossover stripe patterns by selective area epitaxy

“…Optoelectronic materials and devices based on InGaN multiple quantum wells (MQWs) have been developed across the blue and green wavelength range using metal-organic chemical vapor deposition (MOCVD) [1][2][3]. However, for longer wavelengths the efficiency of devices based on GaN grown in the commonly used c-direction is continuously decreasing with increasing indium content in the active region [4].…”