GaInN/GaN multiple-quantum-well light-emitting diodes grown by molecular beam epitaxy

Abstract

GaInN and GaN were grown by molecular beam epitaxy on c-plane sapphire using NH3. 9 K photoluminescence performed on both GaInN thin layers and GaInN/GaN multiple-quantum wells (MQWs) exhibits narrow emission (∼50 meV linewidths). Transmission electron microscopy images show sharp GaInN/GaN interfaces and homogeneous GaInN layers. Strong indium surface segregation is also evidenced. Light-emitting diodes were fabricated from 5×GaInN (25 Å)/GaN (35 Å) MQW heterostructures. The 300 K electroluminescence yields blue light at 440 nm.

Microstructural Investigation of Bilayer Growth of In- and Ga-Rich InGaN Grown by Chemical Vapor Deposition

“…The origin of the phase separation in the InGaN was proposed to occur via mechanisms of spinodal decomposition, 17 surface segregation, 7 and preferred nucleation on open-core dislocations. 8 According to the XTEM observations from different sites of the sample over the millimeter range, HAADF images observed from the ½1120 direction clearly showed that the nucleation of In-rich InGaN was closely related to threading dislocations.…”

“…Large mismatch of lattice parameters between InN and GaN is another known hurdle to the growth of high-quality In-rich InGaN layers. Compositional inhomogeneity has also been reported by many investigators during the growth of InGaN, [5][6][7][8][9][10] which diminishes the device efficiencies of the InGaN/GaN system in commercial light-emitting diodes (LEDs) and laser diodes (LDs).…”

Systematic theoretical investigations for contribution of lattice constraint to novel atomic arrangements in alloy semiconductor thin films

“…Alloy semiconductor thin films including Si 1Àx Ge x , In 1Àx Ga x P, and In 1Àx Ga x N often exhibit various novel atomic arrangements such as atomic ordering and surface segregation [1][2][3][4][5][6][7][8][9]. Previous theoretical studies reveal that these novel atomic arrangements in thin films are closely related to the lattice constraint from the substrate.…”

Dependence of carrier localization in InGaN∕GaN multiple-quantum wells on well thickness

“…Previously, several reports suggested that the localized states may arise from In compositional fluctuation or QD formation, phase separation, monolayer thickness fluctuation, and surface segregation. [16][17][18] Figure 3 shows timeintegrated macro-PL spectra for the unmasked MQW samples together with a micro-PL spectrum for the Al masked sample C recorded at 5 K ͑inset͒ at an excitation power of 15.9 W. The micro-PL spectrum shows QD-like emission on the high-energy side of macro-PL spectrum with a FWHM of 1.65 meV. While sample C exhibited clear QD emission ͑seen in several masked areas͒, we were not able to detect any QD emission from samples A and B and saw no significant spatial variation in the PL intensity.…”