Emission Efficiency in InAs LEDs Controlled by Surface Recombination

Abstract

In this paper, light emitting diodes (LEDs) are used to study the recombination dynamics of minority electrons in p type InAs. The LEDs operate through injecting electrons into p type material with a free surface. When surface recombination is dominant, the output of the LEDs is shown to depend only on the strength of the radiative recombination and not on its efficiency. When surface recombination is not dominant, the dependence of the LED efficiency on the thickness of the active layer is analysed to give the minority carrier diffusion lengths and recombination efficiencies. the electron diffusion lenSgth is shown to be 3±0.5 μm in 5×10⁻¹⁸ cm⁻³ p type InAs and 6±1 pm in 2×10 cm⁻³ p type material. An upper limit of∼2.1×10⁻²⁸ cm⁶ s⁻¹ is deduced for the total Auger recombination rate constant in p type material.