Internal quantum efficiency of high-brightness AlGaInP light-emitting devices

Abstract

The internal quantum efficiency of (AlxGa1−x)0.5In0.5P light-emitting devices (LEDs), with an emission wavelength ranging from 650 to 560 nm, is determined by means of a model that takes into account the radiative and nonradiative recombination in the active layer, the diffusive leakage of carriers into the confining layers, and the influence of photon recycling on the light extraction efficiency. The evaluation is based on measurements of the external quantum efficiency of the LEDs as a function of the operating current and temperature. The analysis provides the wavelength dependence of both the nonradiative recombination as well as the carrier leakage.

Growth, microstructure, and luminescent properties of direct-bandgap InAlP on relaxed InGaAs on GaAs substrates

“…6 There are several reasons behind the poor efficiency of (Al x Ga 1Àx ) 0.52 In 0.48 P (x> 0.3) LEDs, chief among them being: proximity to the direct/indirect-bandgap crossover, and the lack of an electron cladding material. 7,8 The InAlP material system has not been as well studied as the InGaP system, but still has desirable properties. In 0.48 Al 0.52 P is latticematched to GaAs and has an indirect-bandgap, finding application as cladding or window layers for devices.…”

Enhanced Light Extraction in Wafer-Bonded AlGaInP-Based Light-Emitting Diodes via Micro- and Nanoscale Surface Textured

“…[1], [2]. Recent years, the epitaxy quality in AlGaInP material was greatly improved and internal quantum efficiency had already approached to 90% or higher [3] by excellent epitaxy technique. However, the external quantum efficiency is limited owing to the absorbing GaAs substrate and large reflection index different between AlGaInP-based material and outside medium (air or epoxy).…”

Design and analysis of AlGaInP-based light emitting diodes with SiO2current blocking layer

“…However, the light-extraction efficiency is still very low because of the large difference in the refractive index between the GaP window layer and air [2]. Considering this large distinction, only about 5% of internally emitted light from the active region can escape from the surface of devices [3,4]. Further more，the effect of p-pad electrode on light-extraction efficiency is also very important.…”