掺铒对激光烧蚀制备纳米硅晶薄膜形貌的影响

在2×10-4 Pa真空下，采用XeCl准分子激光器(波长308 nm)，调整激光单脉冲能量密度为3 J/cm2，交替烧蚀高纯单晶硅(Si)靶和铒(Er)靶，通过调整辐照两靶的激光脉冲个数比来控制掺Er浓度，分别在Si衬底和石英衬底上制备了掺Er非晶Si薄膜。在N2气保护下经高温热退火实现纳米晶化，退火时间为30 min。采用扫描电子显微镜(SEM)观察所得到的样品的表面形貌显示，铒掺杂影响着薄膜的表面形貌，与不掺Er情况相比，掺入适量的Er可以在较低的退火温度下得到晶粒尺寸分布更均匀的薄膜;拉曼谱的测量结果表明，在相同的退火温度下，Er的掺入有利于晶粒的长大，但同时降低了薄膜的晶化度，掺Er非晶Si薄膜要实现完全晶化需要更高的退火温度。

Influence of Er-Doping on Nanocrystalline Si Films Morphology Fabricated by Pulsed Laser Ablation

Both the single crystalline Si and Er targets are ablated alternately by XeCl excimer laser (wavelength 308 nm) to fabricate Er-doped amorphous Si films on Si and quartz substrates in the vacuum chamber at the pressure of 2×10-4 Pa, and the concentration of Er-doping can be controlled through laser pulse ratio on both Si and Er targets. The samples are subsequently annealed for 30 min in flowing nitrogen. The scanning electron microscope (SEM) images of the samples indicate that more uniform nc-Si films could be achieved at lower annealing temperature by choosing reasonable Er-doping concentration comparing to un-doped samples; The Raman spectra show that Er-doping is valid for the growing of the nanoparticles, but decreases the crystalline degree of the samples at the same annealing temperature. Higher annealing temperature is needed for crystalline of Er-doped amorphous Si films than the amorphous Si films.