退火对Pb辐照Al2O3单晶发光特性的影响

Effects of Annealing on the Photoluminescence of 230 MeV Pb ion Irradiation Sapphire

研究了230MeV的^208Pb^27＋辐照Al2O3样品及随后在600，900，1100K高温条件下退火后的光致发光特性。从辐照样品的测试结果可以清楚地看到在波长为390，450nm处出现了强的发光峰。辐照量为1×10^13ions／cm^2时，样品的发光峰最强。经过600K退火2h后测试结果显示，380nm发光峰剧烈增强，而其他发光峰显示不明显。在900K退火条件下，380nm的发光峰开始减弱，而在360，510nm出现了明显的发光峰，至到1100K退火完毕后380nm的发光峰完全消失，而360，510nm的发光峰相对增强。从被辐照样品的FTIR谱中看到，波数在460～510cm^-1间的吸收是振动模式，经过离子辐照后，吸收带展宽，随着辐照量的增大，Al2O3振动吸收峰消失，说明Al2O3振动模式被完全破坏。1000～1300cm^-1之间为Al-O-Al桥氧的伸缩振动模式，辐照后吸收带向高波数方向移动，说明其振动模式受到影响。辐照剂量较小的样品，损伤程度相对较低，经退火晶化后，振动模式基本恢复到单晶状态；辐照剂量较高的样品，损伤程度大，退火处理后表面变得较粗糙，振动模式并未出现，说明结构破坏严重。

Single crystal sapphire （Al2O3） samples were irradiated by ^208Pb^27＋ ions with energy of 230 MeV to the fluences ranging from 2× 10^12 to 5 × 10^14 ions/cm^2 and subsequently annealed at 600, 900 and 1 100 K temperature. The modification of structure and optical properties induced by ion irradiation were analyzed using photoluminescence（PL） and Fourier Transform infrared（FTIR） spectra measurements. The PL measure-ments showed that absorption peaks located at 390 nm and 450 nm appeared in irradiated samples, the PL intensities reached up to the maximum for the sample irradiated with the fluence of 1 × 10^13 ions/cm^2. The peak of 380 nm became very intensive after 600 K anneal and other peaks are very weak. After annealing at 900 K,the peak of 380 nm weaken and 360 nm, 510 nm peak start buildup, the peak of 380 nm entirely vanished and 360 nm, 510 nm peak increasing along with annealing temperature at 1 100 K. From the obtained FTIR spectra, it was found that Pb-ion irradiation induced broadening of the absorption band in 460 - 510 cm^-1 and position shift of the absorption band in 1 000 - 1 300 cm^-1 towards to high wavenumber. Those indicated that the vibration structure affected by Xe ion irradiation. The possible mechanism of damage in single crystal sapphire induced by irradiation was briefly discussed.