Electroluminescence from Er-doped GeO₂ nanofilms fabricated by atomic layer deposition on silicon: Effect of annealing temperature on film properties

Er-doped GeO2 (GeO2:Er) nanofilms are fabricated by atomic layer deposition on silicon, from which the 1530 nm electroluminescence (EL) is achieved. The GeO2:Er nanofilms maintain the amorphous structure after annealing at 600-1000 degrees C, while the annealing above 800 degrees C results in the loss of Ge due to the volatile GeOx (x < 2) species. These GeO2:Er nanofilms could withstand the wet lithography process and the prototype devices could operate under the constant current. The 650 degrees C annealed GeO2:Er devices manifest the threshold of similar to 40 V and 10(-7) A, while the maximum injection current is 0.28 A/cm(2). The EL power density from the device doped with 3.09 mol% Er reaches to 2.2 mW/cm(2), with the external quantum efficiency of 7.3% and power efficiency of 0.17%. The conduction mechanism for the excitation of Er emission confirms to the trap-assisted tunneling mode within the amorphous GeO2:Er nanolaminates. This work demonstrates the potential of GeO2:Er nanofilms in the utilization of Si-based optoelectronics.