Proton radiation damage at low temperature in GaAs and GaN light-emitting diodes

It is shown that the radiation hardness for light emission in light-emitting diodes (LEDs) is substantially improved at low temperatures. This is demonstrated through measurements of light emission at room and low temperatures from amphoteric Si-doped gallium arsenide, gallium arsenide quantum well and gallium nitride quantum well LEDs following proton irradiation at room and low temperatures. The enhanced low-temperature radiation hardness for light emission in these LEDs is explained in terms of an improvement in radiative efficiency due to a reduction of nonradiative transition probability at low temperatures. Further, lattice displacement damage in these devices due to irradiation at room temperature is compared with the corresponding damage at low temperatures. Our results show that the amount of lattice damage is dependent on irradiation temperature.