Formation of Fe-N films containing Fe6N2 phase by ion beam assisted deposition

Fe-N films were deposited on Si(100) and GaAs(100) substrates at room temperature by ion beam assisted deposition under various N/ Fe atomic arrival ratio, 0.09, 0.12, 0.15. The results of X-ray diffraction indicated that the film deposited at 0.12 of N/Fe arrival ratio contained a considerable fraction of the Fe16N2 phase which had grown predominantly in the [001] orientation. For the larger N/Fe arrival ratio, a martensite phase with 15 at.% nitrogen was obtained. It was found that a lower deposition temperature (<200 degrees C) was necessary for the formation of the Fe16N2 phase.

PHOTOINDUCED CHANGES OF HYDROGEN-BONDING IN SEMIINSULATING IRON-DOPED INDIUM-PHOSPHIDE

After illumination with 1-1.3 eV photons during cooling-down, metastable PH modes are observed by IR absorption at 5 K in semi-insulating InP:Fe. They correlate with the photo-injection of holes, but not with a change of the charge state of the K-related centres present at equilibrium. They are explained by a change of the bonding of H, induced by hole trapping, from IR-inactive centres to PH-containing centres, stable only below 80 K. One metastable centre has well-defined geometrical parameters and the other one could be located in a region near from the interface with (Fe,P) precipitates.

Investigation on Fe, Mn, Zn, Cu, Pb and Cd fractions in the natural surface coatings sampled and surficial sediments collected in the Songhua River, China

Natural surface coatings sampled (NSCSs) from the surface of shingles and surficial sediments (SSs) in the Songhua River, China were employed to investigate the similarities and difference in fractions of heavy metals (Fe, Mn, Zn, Cu, Pb, and Cd) between NSCSs and SSs using the modified sequential extraction procedure (MSEP). The results show that the differences between NSCSs and SSs in Fe fractions were insignificant and Fe was dominantly present as residual phase (76.22% for NSCSs and 80.88% for SSs) and Fe-oxides phase (20.33% for NSCSs and 16.15% for SSs). Significant variation of Mn distribution patterns between NSCSs and SSs was observed with Mn in NSCSs mainly present in Mn-oxides phase (48.27%) and that in SSs present as residual phase (45.44%). Zn, Cu, Pb and Cd were found dominantly in residual fractions (>48%), and next in solid oxides/hydroxides for Zn, Pb and Cd and in easily oxidizable solids/compounds form for Cu, respectively. The heavy metal distribution pattern implied that Fe/Mn oxides both in NSCSs and SSs were more important sinks for binding and adsorption of Zn, Pb and Cd than organic matter (OM), and inversely, higher affinity of Cu to OM than Fe/Mn oxides in NSCSs and SSs was obtained. Meanwhile, it was found that the distributions of heavy metals in NSCSs and SSs were similar to each other and the pseudo-total concentrations of Zn, Cu, Pb and Cd in NSCSs were greater than those in SSs, highlighting the more importance for NSCSs than SSs in controlling behaviours of heavy metals in aquatic environments.

低能离子束方法制备磁性Fe-Si合金薄膜

利用质量分离的低能离子束技术,获得了磁性Fe-Si合金薄膜.利用俄歇电子能谱法(AES)、X射线衍射法(XRD)以及交变梯度样品磁强计(AGM)测试了样品的组分、结构以及磁特性.测试结果表明在室温下制备的Fe-Si合金是Fe组分渐变的非晶薄膜,具有室温铁磁性.当衬底温度为300℃时制备的非晶Fe-Si薄膜中有Fe硅化物FeSi相产生,样品的铁磁性被抑制.

低能离子束方法制备重掺杂Fe的Si:Fe固溶体

利用质量分离的低能离子束方法,以离子能量为1000eV,剂量为3×1017cm-2,室温下往p型Si(111)单晶衬底注入Fe离子,注入的样品在400 C真空下进行热处理.俄歇电子能谱法(AES)对原位注入样品深度分析表明Fe离子浅注入到p型Si单晶衬底,注入深度约为42nm.X射线衍射法(XRD)对热处理样品结构分析发现只有Si衬底的衍射峰,没有其他新相.X射线光电子能谱法(XPS)对热处理样品表面分析发现Fe2p束缚能对应于单质Fe的峰,没有形成Fe的硅化物.这些结果表明重掺杂Fe的Si:Fe固溶体被制备.电化学C-V法测量了热处理后样品载流子浓度随深度的分布,发现Fe重掺杂Si致使Si的导电类型从p型转为n型,Si:Fe固溶体和Si衬底形成pn结,具有整流特性.

低能离子束方法制备Fe组分渐变的Fe-Si薄膜

利用质量分离的低能离子束技术，获得了Fe组分渐变的Fe-Si薄膜。利用俄歇电子能谱法(AEs)、x射线衍射法(XRD)以及x射线光电子能谱法(XPS)测试了薄膜的组分、结构特性。测试结果表明，在室温下制备的Fe-Si薄膜呈非晶态。非晶薄膜在400℃下退火20 rmn后晶化，没有Fe的硅化物相形成。退火后Fe-Si薄膜的Fe组分从表面向内部逐渐降低。

Influence of Fe Doping Concentration on Some Properties of Semi-Insulating InP

Properties of Fe-doped semi-insulating (SI) InP with different iron concentrations are studied by using Hall effect, current-voltage (I-V), photoluminescence spectroscopy (PL) and photocurrent spectroscopy (PC) measurements. I-V characteristics of SI InP strongly depend on Fe doping concentration. Fe doping concentration also influences optical properties and defective formation in as-grown SI InP. Band-gap narrowing phenomenon and defects in Fe doped SI InP are studied using PI and PC.

Investigation of Residual Donor Defects in Undoped and Fe-Doped LEC InP

The free electron concentration of as-grown liquid encapsulated Czochralski (LEC) InP measured by Hall effect is much higher than the concentration of net donor impurity determined by glow discharge mass spectroscopy. Evidence of the existence of a native donor hydrogen-indium vacancy complex in LEC undoped and Fe-doped InP materials can be observed with infrared absorption spectra. The concentration increase of the donor complex correlates with the increase of ionized deep acceptor iron impurity Fe~(2+) concentration in Fe-doped semi-insulating (SI) InP. These results indicate that the hydrogen-indium vacancy complex is an important donor defect in as-grown LEC InP, and that it has significant influence on the compensation in Fe-doped SI InP.

硅双极晶体管的低温h_（FE）

低温下h_(FE)主要决定于发射效率γ和集电区倍增因子M。影响γ的是禁带收缩和基区费米能级。M则主要由中性杂质被碰撞电离而造成的电流倍增效应决定，并且这是一种自抑制效应。以上观点与实验结果基本相符合。