In0.53Ga0.47As/InP量子阱与体材料的1 MeV电子束辐照光致发光谱研究∗

摘要

Minimizing the impact of radiation-induced degradation on optoelectronic devices is important in several applica-tions. Satellites and other spacecraft that fly in near-earth orbits (below 3.8 earth radius) are extremely susceptible to radiation damage caused by the high flux of electrons trapped in the earth’s magnetosphere. Optoelectronic devices are particularly vulnerable to displacement damage caused by electrons and protons. Effects of 1 MeV electron beam irradiation on the photoluminescence properties of In0.53Ga0.47As/InP quantum well (QW) and bulk structures, which are grown by metal-organic vapor phase epitaxy, are investigated. Samples are irradiated at room temperature using an ELV-8II accelerator with 1 MeV electron at doses ranging from 5 × 1012 to 9 × 1014 cm−2, and a dose rate of 1.075 × 1010 cm−2·s−1. Photoluminescence measurements are made using a 532 nm laser for excitation and a cooled Ge detector with lock-in techniques for signal detection. Photoluminescence intensity of all the structures is degraded after irradiation, and its reduction increases with increasing total dose of irradiation. Electron beam irradiation causes a larger reduc-tion in the photoluminescence intensity and carrier lifetime of the bulk than that of quantum well. Photoluminescence intensity of five-layer quantum wells degenerates to 9% that before irradiation as the fluence reaches 6 × 1014 cm−2. As the electron beams bombard into the sample, the destruction of the lattice integrity will cause the decrease in the number of excitons and intensity of photoluminescence. Electron beam irradiation introduces defects in the samples, increases the density of the nonradiative recombination centers, and results in the decrease of carrier mobility. In a quantum well structure, due to the two-dimensional confinement, the probability of carrier nonradiative recombination at radiation-induced defect centers will be reduced. The reduction of photoluminescence intensity in the bulk is severer than in the quantum well while the cross-sectional area which is sensitive to radiation is kept the same. The number of interface defects which are produced by electron irradiation will increase with the number of layers in quantum well and the heterojunction interface of quantum wells, so is the degration of photoluminescence intensity. The degration is mainly due to the increase of non-radiative centers in the samples. By comparing the different structures, the quantum well structure shows a better radiation resistance.