Graded InxGa1−xAs/GaAs 1.3 μm wavelength light emitting diode structures grown with molecular beam epitaxy

Abstract

In this study 1.1–1.3 μm wavelength light emitting diode (LED) structures with InxGa1−xAs compositionally graded buffers were grown on GaAs substrates with molecular beam epitaxy and characterized using microstructure and discrete device characterization techniques. The growth temperature and design of the graded buffer greatly affect the luminescence properties of the active device region above the graded buffer. These effects were most prominent in LED structures which incorporated a quantum well in the active device region. In quantum well devices, bright luminescent bands in the 〈110〉 directions are revealed under cathodoluminescence investigation and the number of bands and their intensity depend on grading rate. This study shows that a high threading dislocation density generated at or above the quantum well region has an adverse effect on the I–V characteristics of the diodes, but did not hinder luminescence from the quantum well LEDs.