Recombination mechanisms and band alignment of GaAs1-xBix/GaAs light emitting diodes

We investigate the temperature and pressure dependence of the light-current characteristics and electroluminescence spectra of GaAs1-xBix/GaAs light emitting diodes. The temperature dependence of the emission wavelength shows a relatively low temperature coefficient of emission peak shift of 0.19 +/- 0.01 nm/K. A strong decrease in emission efficiency with increasing temperature implies that non-radiative recombination plays an important role on the performance of these devices. The pressure coefficient of the GaAs0.986Bi0.014 bandgap is measured to be 11.8 +/- 0.3 meV/kbar. The electroluminescence intensity from GaAsBi is found to decrease with increasing pressure accompanied by an increase in luminescence from the GaAs cladding layers suggesting the presence of carrier leakage in the devices. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3681139]