一种高透过率,深截止的UVc波段(200～280 nm) 有机材料的研究(Ⅰ)

本文阐述了一种专用有机材料(粉末)在不同酸性溶液中的光谱特征,研究表明,这种材料在λ=252 nm处,透过率T=56.5％,带宽约为16nm,而在λ=290nm处有一个很强的吸收峰(ε>10L·(mol·cm)~(-1)),吸光度A_(280～298nm)>8,即透过率T_(280～298nm)<10~(-8)。这种有机材料在UVc波段(200～280nm)具有高透过率,深截止的明显特点。实验中还发现,通过调节溶剂的pH值和选取不同极性的溶剂,原来的两个吸收峰消失,而在λ=290nm处出现一个新的强吸收峰,并且透过峰可以在251～260nm范围内移位。利用材料的这种特征,再配合传统的镀膜和色玻璃技术,有可能制备出性能优良的紫外滤光片。     

星状C60(CH3)x(PAN)x共聚物的光致发光研究

利用物理喷束淀积（ＰＪＤ）技术制备Ｃ６０（ＣＨ３）ｘ（ＰＡＮ）ｘ共聚物的薄膜。这种共聚物中,Ｃ６０分子位于星状结构的中心,聚丙烯腈（ＰＡＮ）主链修饰在Ｃ６０分子的周围。吸收及荧光光谱表明：Ｃ６０分子与聚丙烯腈（ＰＡＮ）有明显的相互作用,而且这种相互作用与ＰＡＮ的链长有关。Ｃ６０分子与ＰＡＮ间存在一定的激发传递过程,从而导致ＰＡＮ荧光的部分猝灭。     

Influence of patterned TiO2/SiO2 dielectric multilayers for back and front mirror facetson GaN-based laser diodes

Ridge InGaN multi-quantum-well-structure （MQW） edge-emitting laser diodes （LDs） were grown on （0001） sapphire substrates by low-pressure metal-organic chemical vapour deposition （MOCVD）. The dielectric TiO2/SiO2 front and back facet coatings as cavity mirror facets of the LDs have been deposited with electron-beam evaporation method. The reflectivity of the designed front coating is about 50% and that of the back high reflective coating is as high as 99.9%. Under pulsed current injection at room temperature, the influences of the dielectric facets were discussed. The threshold current of the ridge GaN-based LDs was decreased after the deposition of the back high reflective dielectric mirrors and decreased again after the front facets were deposited. Above the threshold, the slope efficiency of the LDs with both reflective facets was larger than those with only back facets and without any reflective facets. It is important to design the reflectivity of the front facets for improving the performance of GaN-based LDs.