氮化铝铬的制备及其光学性质

Synthesis and Photoluminescence Properties of Cr^(3+) Doped Aluminium Nitride

利用直接氮化法得到了氮化铝和氮化铬,并用两种途径得到Cr3+掺杂的氮化铝样品。用X射线衍射仪分析了样品晶相并测试了两种样品的激发和发射光谱,计算了晶体场劈裂参数Dq和Racah参数B及Dq/B分别为1 800,693.69和2.59。光谱数据表明,Cr3+在氮化铝中属于强场环境,光发射来自于最低激发态2E能级,与在氧化铝中的环境相似。根据光谱数据给出了Cr3+在氮化铝晶体场中的能级。

Aluminium nitride and chromium nitride were synthesized by high temperature solid state method with aluminium,chromium and high purity nitrogen.Two types of methods were used to obtain Cr3＋-doped AlN： one is to nitride mixtures of aluminium and chromium,the other is to heat aluminium nitride and chromium nitride at 1 400 ℃ for 3 h under nitrogen.X-ray diffraction analyzer was used to measure the crystal structure of obtained samples.The excitation and emission spectra of the samples were measured by spectrometer.The obtained data showed that the excitation and emission spectra of Cr3＋∶AlN obtained by two methods are similar,two broad excited bands,peak at 400 nm and 500 nm,and the emission peak at 696 nm,while the intensity of the latter was higher than that of the former due to higher annealing temperature.According to the excitation and emission spectra of Cr3＋∶AlN,Dq/B and the energy levels of Cr3＋ion in AlN were given.The obtained data showed that the emission of Cr3＋at 696 nm came from the first excited state 2E,which is similar to that of Cr3＋ in Al2O3 host.