Ultralow recombination velocity at Ga0.5In0.5P/GaAs heterointerfaces

Abstract

Using time-resolved photoluminescence, we have examined the optoelectronic properties of Ga0.5In0.5P/GaAs/Ga0.5In0.5P double heterostructures grown by organometallic chemical vapor deposition. For comparison, similar structures using Al0.4Ga0.6As/GaAs and Al0.5In0.5P/GaAs lattice-matched heterointerfaces were also examined. For the Ga0.5In0.5P/GaAs heterostructure, we show that the recombination velocity at a Ga0.5In0.5P/GaAs interface can be less than 1.5 cm/s. As a result, photoluminescence decay times as long as 14 μs have been observed in undoped GaAs double heterostructures. This photoluminescence decay time varies with temperature as T1.59, characteristic of radiative recombination not limited by surface or bulk nonradiative recombination processes. For the Al0.4Ga0.6As/GaAs and Al0.5In0.5P/GaAs heterostructures examined in this study, the upper limits of the interface recombination velocity were 210 and 900 cm/s, respectively.

Passivation of Interfaces in High-Efficiency Photovoltaic Devices

“…The Ga 0.5 In 0.5 P/GaAs twojunction solar cell, invented and developed at NREL, has achieved high efficiencies of around 30% [1][2][3] and is in large-scale production [4,5]. We have shown that very low (as low as 1.5 cm/s [6]) interface recombination velocities (IRV) can be achieved for the Ga 0.5 In 0.5 P/GaAs interface. However, in actual device structures, much higher IRVs are often observed.…”

Circularly polarized luminescence microscopy for the imaging of charge and spin diffusion in semiconductors

“…17 Note that since vertical diffusion over a distance larger than the effective depth of field of the microscope objective results in a defocused luminescence spot, The spectra in Fig. 1 are obtained via a 50 m diameter optical fiber whose diameter corresponds to a spot of diameter l ~ 1 m on the images of Fig.…”

Determination of CdTe bulk carrier lifetime and interface recombination velocity of CdTe/MgCdTe double heterostructures grown by molecular beam epitaxy

“…1) are two popular materials for high efficiency solar cells. It has been found that many materials, such as AlGaAs and GaInP, [2][3][4][5][6] provide sufficient carrier confinement to GaAs, which prevents carriers from reaching the top surface of the epilayers and thus effectively reduces the surface recombination rate by providing a heterojunction interface. The interface recombination velocity (IRV) of a high quality GaAs/Al 0.5 Ga 0.…”