Dependence of composition fluctuation on indium content in InGaN/GaN multiple quantum wells

Abstract

The information on the variations of indium composition, aggregation size, and quantum-well width is crucially important for understanding the optical properties and, hence, fabricating efficient light-emitting devices. Our results showed that spinodal decomposition could occur in InGaN/GaN multiple quantum wells with indium content in the range of 15%-25% ͑grown with metal-organic chemical-vapor deposition͒. A lower nominal indium content led to a better confinement of indium-rich clusters within InGaN quantum wells. The InGaN/GaN interfaces became more diffusive, and indium-rich aggregates extended into GaN barriers with increasing indium content. It was also observed that indium-rich precipitates with diameter ranging from 5 to 12 nm preferred aggregating near V-shaped defects.

Influence of electron distribution on efficiency droop for GaN-based light emitting diodes

“…In addition, the full width at half maximum of the (002) rocking curve are 277.6, 244.6 and 279.6 arcsec for LED I, LED II and LED III, respectively, indicating that LED II has a better total crystal quality than the LED I and LED III. The reason may be due to the reduced lattice mismatch and misfit dislocation between the MQWs, but with the indium concentration further increasing, the barrier crystal quality becomes worse due to the indium incorporation [24]. The thicknesses of MQWs and the distributions of indium concentration in the MQW were measured using the bright field transmission electron microscope (BF-TEM) and the secondary ion mass spectroscopy (SIMS).…”

Inorganic Semiconductors for Light‐emitting Diodes

“…1.4 have an active region comprised of a ternary or quaternary alloy, e. g. Ga 1-x In x N. In this case, alloy broadening leads to spectral broadening that goes beyond 1.8kT. Alloy broadening due to inhomogeneous distribution of In in the active region of green Ga 1-x In x N LEDs can cause linewidths as wide as 10kT at room temperature [1]. It should be noted, however, that a recent study found inhomogeneous strain distribution in GaInN quantum wells as a result of electron damage during TEM experiments [2].…”

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

“…The strain caused by lattice mismatch between InGaN wells and GaN barriers may increase with the raise of indium composition in the QWs. Indium clustering induced by a misfit strain is obser− ved when the well thickness is smaller than the critical thickness [5]. However, if the well is thicker than the critical thickness, the misfit strain may cause the misfit strain−in− duced defects such as point defects [6], impurities [7], V−de− fects [8,9].…”