Direct observation of the distribution of impurity in phosphorous/boron co-doped Si nanocrystals

Doping in Si nanocrystals is an interesting topic and directly studying the distribution of dopants in phosphorous/boron co-doping is an important issue facing the scientific community.In this study,atom probe tomography is performed to study the structures and distribution of impurity in phosphorous/boron co-doped Si nanocrystals/SiO_(2) multilayers.Compared with phosphorous singly doped Si nanocrystals,it is interesting to find that the concentration of phosphorous in co-doped samples can be significantly improved.Theoretical simulation suggests that phosphorous-boron pairs are formed in co-doped Si nanocrystals with the lowest formation energy,which also reduces the formation energy of phosphorous in Si nanocrystals.The results indicate that co-doping can promote the entry of phosphorous impurities into the near-surface and inner sites of Si nanocrystals,which provides an interesting way to regulate the electronic and optical properties of Si nanocrystals such as the observed enhancement of conductivity and sub-band light emission.

Fe_(78)B_(13)Si_9 纳米晶合金的晶体结构

用高密度电脉冲处理Ｆｅ７８Ｂ１３Ｓｉ９（Ｍｅｔｇｌａｓ２６０５Ｓ２）非晶合金，形成了纳米晶合金，并用Ｘ射线衍射和透射电镜研究了纳米晶合金的晶粒结构，结果表明，两个晶体相为αＦｅ（Ｓｉ）固溶体和Ｆｅ２Ｂ（ｂｃｔ）化合物，晶粒尺寸为１９ｎｍ．αＦｅ（Ｓｉ）相的晶格参数为ａ＝０２８５６８ｎｍ，Ｆｅ２Ｂ的晶格参数为ａ＝０５１４５ｎｍ和ｃ＝０４２４９ｎｍ．随电脉冲时间的增加，晶粒尺寸略有增加，而晶格参数则相应降低．αＦｅ（Ｓｉ）相晶格参数的减小与晶粒的微弱生长及由此引起的αＦｅ（Ｓｉ）相中的Ｓｉ含量增加有关．而Ｆｅ２Ｂ（ｂｃｔ）相晶格参数的减小是由该相在电脉冲处理过程中较为明显的生长所引起的．

Cr-Si合金钢表面纳米晶热稳定性的研究

采用超音速微粒轰击技术在Cr-Si合金钢的表面制备了纳米结构层。最表面层的晶粒尺寸约为16nm。利用X射线衍射(XRD)技术和透射电镜(TEM)分析技术对退火后表面纳米晶的结构变化进行分析。结果显示:当温度低于450℃进行退火时,表面纳米晶的尺寸变化不大。当退火温度达到450℃时,表面纳米晶失去稳定急剧长大到100nm左右。分析表明在低于450℃时,Cr-Si合金钢表面纳米晶具有良好的热稳定性,表面纳米晶的本征结构、退火时结构的动态回复以及渗碳体颗粒对晶界运动的阻碍是决定其具有一定的热稳定性的主要因素。

Microstructure Modification of Silicon Nanograins Embedded in Silicon Nitride Thin Films

Microstructure modification of silicon nanograins embedded in silicon nitride films by introducing hydrogen reactant in the plasma enhanced chemical vapour deposition process and their optical properties are analysed using Raman scattering, optical absorption and photoluminescence （PL） measurements. It is found that the silicon nanograins embedded in the silicon nitride （SiNx） matrix are transformed into silicon nanocrystals and the optical properties of the films change dramatically when introducing H2 into Ar-sustained plasma. The optical absorption coefficient of the films within the band gap decreases by about one order of magnitude and the PL intensity increases significantly, compared with that without hydrogen introduction. These results suggest that atomic hydrogen in the plasma has the function of crystallizing silicon nanograins and passivating defects at the silicon nanograins/SiNx interface.

Fe_（78）B_（13）Si_9非晶合金纳米晶化的亚结构

用高密度脉冲电流处理Ｆｅ７８Ｂ１３Ｓｉ９非晶合金，随电流密度的变化在不同的温度下和相同的时间内实现了试样的纳米晶化．透射电镜观察及Ｘ射线衍射分析表明，在由电脉冲方法所制备的纳米晶Ｆｅ７８Ｂ１３Ｓｉ９合金中存在着亚晶和孪晶等亚结构．三种晶化相是α－Ｆｅ（Ｓｉ），Ｆｅ２Ｂ和少量的Ｆｅ３Ｂ．随着电流密度的增加，试样中的Ｆｅ２Ｂ相略有增加并出现了有序的Ｆｅ３Ｓｉ结构，但平均晶粒尺寸保持不变，由Ｓｈｅｒｒｅｒ方法估算为２０～３０ｎｍ．

电脉冲作用下非晶Fe_(78)B_(13)Si_9的晶化及演变

用直流高密度电脉冲处理Fe78B13 Si9非晶合金 ,并用透射电子显微镜 (TEM)和X射线衍射 (XRD)研究了电脉冲处理试样的结构。实验结果表明 ,在所用电脉冲参数 (J =136 0A/mm2 ,τp=40 μs ,f =18Hz)下 ,Fe78B13 Si9非晶试样可实现低温快速纳米晶化 (脉冲处理时间tp=8min ,试样温度T =42 0℃ ) ,晶化相为α Fe(Si)和Fe2 B ,平均晶粒尺寸约为 30nm。随电脉冲处理时间的增加 ,部分α Fe(Si)相开始呈枝晶型生长 ,并出现DO3

激光晶化制备Fe基纳米软磁材料的研究进展

综述了激光非晶晶化制备Fe基纳米软磁材料的国内外研究进展和现状。介绍了Fe基纳米软磁材料的双相组织结构和性能特征及应用领域;对比分析了传统退火晶化和激光晶化制备技术的优缺点;阐述了研究激光纳米晶化技术的重要意义和理论价值。提出了激光晶化技术制备Fe基纳米软磁材料需要重点系统研究的课题和方向。

Enhancement of sensitized photoluminescence of erbium chloride silicate through regulating annealing

Erbium chloride silicate(ECS)nanocrystals and Si nanocrystals(Si NCs)co-embedded in silica films were prepared.And the sensitized luminescence of ECS was realized through interparticle energy transfer(IPET)in solid matrix.We focus on the effect of annealing temperature on the film microstructure and sensitized luminescence.The samples annealed at 1100℃have a moderate level of energy transfer efficiency and total Er3+concentration capable of radiative recombination.At the same time,they also have high luminescence intensity of Si NCs.Therefore,the samples annealed at 1100℃have good sensitizing luminescence performance of ECS.The strong luminesce nce intensity of sensitizers Si NCs and adjacent crystalline ECS nanocrystals are the keys to achieve excellent IPET in the solid matrix.The results provide a basis for optimizing sensitized luminescence of erbium compounds by regulating annealing.

Effects of Si implantation on the total dose hardness of fully-depleted SIMOX wafers

Total dose hardened fully-depleted SOI materials are fabricated on separation by implanted oxygen （SIMOX） materials by silicon ion implantation and annealing. The ID-VG characteristics of pseudo-MOS transistors pre- and post-irradiation are tested with ^60Co gamma rays. The chemical bonds and the structure of Si in the buried oxide are also studied by X-ray photoelectron spectroscopy and cross-sectional high-resolution transmission electron microscopy, respectively. The results show that Si nanocrystals in the buried oxide produced by ion implantation are efficient deep electron traps, which can significantly compensate positive charge buildup during irradiation. Si implantation can enhance the total-dose radiation tolerance of the fully-depleted SOI materials.

光伏硅弃料制备锂离子电池硅负极的性能

纯硅的导电性差,且纳米化、非晶化技术成本高。光伏行业用硅的产业化程度高、导电性好,弃料可在锂离子电池硅基负极实现再利用。以光伏硅弃料为原料,采用机械球磨法制备纳米硅和非晶/纳米硅材料。制备的材料均具有较高的可逆比容量和稳定的循环性能,以0.2 C在0.005~0.900 V循环100次,纳米硅剩余的比容量为2 123.32 mAh/g,非晶/纳米硅剩余的比容量为1 367.70 mAh/g。