CZNTD Si中氧碳对缺陷-杂质复合体行为的影响

本文研究了CZNTD Si中氧碳和缺陷-杂质复合体的热处理行为.分析了辐照和退火中的氧碳沉淀、缺陷-杂质复合体的形成、演变与施主的关系.确定了辐照施主是很少的,而主要是退火中形成的新施主,并且碳对这种施主起着强烈的促进作用.     

高质量InAs单晶材料的制备及其性质

利用液封直拉法(LEC)生长了直径50mm〈100〉和〈111〉晶向的InAs单晶.分析研究了n型杂质Sn,S和p型杂质Zn,Mn的分凝特性、晶格硬化作用、掺杂效率等.利用X射线双晶衍射分析了晶体的完整性.对InAs晶片的抛光、化学腐蚀和清洗进行了分析,在此基础上实现了抛光晶片的开盒即用(EPI-READY).     

高质量InAs单晶材料的制备及其性质

利用液封直拉法(LEC)生长了直径50mm〈100〉和〈111〉晶向的InAs单晶.分析研究了n型杂质Sn,S和p型杂质Zn,Mn的分凝特性、晶格硬化作用、掺杂效率等.利用X射线双晶衍射分析了晶体的完整性.对InAs晶片的抛光、化学腐蚀和清洗进行了分析,在此基础上实现了抛光晶片的开盒即用(EPI-READY).     

施主型杂质对单晶硅中少子衰减过程的影响

单晶硅材料内少子的衰减过程可以反映出其内部杂质和缺陷的信息。针对施主型杂质是单晶硅内多数杂质呈现的基本形态,首先在小注入条件下分析了p型单晶硅内少子衰减的基本机制,然后根据施主型杂质密度、俘获截面和能级距导带底之间距离等参数的不同,重点讨论了存在施主型电子陷阱和复合中心时,太阳电池用p型单晶硅内少子衰减的基本规律。研究表明:存在施主型电子陷阱或复合中心时,p型单晶硅的少子衰减过程具有恒定的少子寿命,且杂质的密度N_T和俘获截面σ_n之积(N_T×σ_n)存在最小的影响阈值,N_T×σ_n值大于阈值的杂质和缺陷对少子衰减过程才具有重要的影响。     

掺Sb的ZnO单晶的缺陷和性质研究

采用化学气相传输法生长了掺Sb的ZnO体单晶,生长温度为950℃. 与非掺ZnO单晶相比,掺Sb后ZnO单晶仍为n型,其自由电子浓度明显升高. X射线光电子能谱（XPS）测量结果表明,掺入的Sb在ZnO单晶中可能占据了Zn位,或处于间隙位置,形成了施主. 利用光致发光谱（PL）测量发现掺Sb后ZnO单晶发出蓝光,该蓝色荧光与浅施主有关. 这些结果表明在高温生长条件下,掺Sb后ZnO单晶中产生了高浓度的施主缺陷,因而难以获得p型材料.     

非掺及掺铁磷化铟中的残留施主缺陷

用辉光放电质谱(GDMS)测量了原生液封直拉(LEC)磷化铟(InP)的杂质含量.利用霍尔效应测到的非掺LEC-InP的自由电子浓度明显高于净施主杂质的浓度.在非掺和掺铁InP中都可以用红外吸收谱测到浓度很高的一个氢-铟空位复合体施主缺陷.这个施主的浓度随着电离的铁受主Fe2+浓度的增加而增加.这些结果表明半绝缘体中氢-铟空位复合体施主缺陷的存在对铁掺杂浓度和电学补偿都有重要影响.     

非掺及掺铁磷化铟中的残留施主缺陷

用辉光放电质谱(GDMS)测量了原生液封直拉(LEC)磷化铟(InP)的杂质含量.利用霍尔效应测到的非掺LEC-InP的自由电子浓度明显高于净施主杂质的浓度.在非掺和掺铁InP中都可以用红外吸收谱测到浓度很高的一个氢-铟空位复合体施主缺陷.这个施主的浓度随着电离的铁受主Fe2+浓度的增加而增加.这些结果表明半绝缘体中氢-铟空位复合体施主缺陷的存在对铁掺杂浓度和电学补偿都有重要影响.     

掺Sb的ZnO单晶的缺陷和性质研究

采用化学气相传输法生长了掺Sb的ZnO体单晶,生长温度为950℃.与非掺ZnO单品相比,掺Sb后ZnO单晶仍为n型,其自由电子浓度明显升高.x射线光电子能谱(XPS)测量结果表明.掺人的Sb在ZnO单晶中可能占据了Zn位,或处于间隙化置,形成了施主.利用光致发光谱(PL)测量发现掺Sb后ZnO单晶发出蓝光,该蓝色荧光与浅施主有关.这些结果表明在高温生长条件下,掺Sb后ZnO单晶中产生了高浓度的施主缺陷,因而难以获得P型材料.     

Ⅲ、Ⅴ族杂质对硅中热施主性质的影响

首次利用导纳谱技术研究了450℃处理后的CZ-Si.导纳谱、DLTS和霍耳测量的结果表明:热施主有四个施主能级,即 E_c-(330～280)meV、E_c- 120meV、E_c-52meV和E_c- 30 meV.同时证明:Ⅲ族和Ⅴ族杂质对这些能级的影响不同.对Ⅲ族杂质增强热施主形成的效应和目前已报道的有关热施主能级的分歧进行了详细研究和讨论.本文指出,用一个统一微观模型说明热施主的各种性质似乎不妥,并对这四个施主能级可能的缺陷结构进行了简单探讨.     

有源层表面性质对晶硅电池暗 I-V 特性的影响

利用有限差分法求解半导体器件基本方程,研究了表面悬键、杂质和缺陷对晶硅电池输出参数的影响。研究表明:当晶硅电池无体内缺陷和表面缺陷或当仅存在表面悬键、杂质和缺陷,且三者起施主型和受主型陷阱作用时,正向偏压下的晶硅电池暗I-V特性曲线与理想二极管I-V特性曲线相同,但当正向偏压大于PN开启电压0.59V,晶硅电池暗I-V特性曲线将偏离理想二极管I-V特性曲线,且偏离程度随表面悬键、杂质和缺陷浓度的增加而增大;当表面悬键、杂质和缺陷起复合中心作用时,晶硅电池暗I-V特性曲线将偏离理想二极管I-V特性曲线;就对暗I-V特性曲线的影响而言,复合中心最大,施主型次之,受主型最小。     

Residual impurities and electrical properties of undoped LEC InAs single crystals

Impurities and their influence on the properties of InAs single crystals have been studied by combining the results of glow discharge mass spectrometry (GDMS), Hall measurements, Raman scattering and infrared absorption. The results indicate that carbon is a major impurity in LEC-InAs single crystals and exhibits a significant influence on the electrical and optical properties.     

铟掺杂ZnO体单晶的生长及其性质

研究了In掺杂n型zno体单晶的化学气相传输法生长和材料性质.利用霍尔效应、x射线光电子能谱、光吸收谱、喇曼散射、阴极荧光谱等手段对晶体的特性和缺陷进行r分析.掺In后容易获得浓度为1018～lO19cm-3的n型ZnO单晶,掺人杂质的激活效率很高.随着掺杂浓度的提高,znO单晶的带边吸收和电学性质等发生明显的变化.分析了掺In-ZnO单晶的缺陷及其对材料性质的影响.     

Formation of built-in potential in Si (100) crystals under microwave plasma treatment

A study of the fundamental aspects of the influence exerted on the electronic properties of a surface of Si (100) single crystals with a natural oxide coating by low-energy microwave plasma treatment in various plasma-forming media is reported. Model mechanisms of the process and factors providing stable modification of the electronic properties of the surface of silicon crystals via the formation of built-in surface potentials determined by the chemical activity of working gases used in plasma microtreatment under weak-adsorption conditions are considered. It is shown that, in principle, the electronic properties of the surface of semiconductor crystals can be actively formed to extend their electrical and functional properties.     

铟掺入对铌镁酸铅钛酸铅单晶声表面波的影响

近十几年,新型弛豫铁电单晶铌镁酸铅-钛酸铅受到广泛关注。但温度稳定性稍差限制了其应用范围。为了进一步改善铌镁酸铅-钛酸铅单晶的声表面波性能,文章利用部分波法研究了铟元素掺入对铌镁酸铅-钛酸铅晶体声表面波性能的影响。结果表明,铟的掺入在提高晶体稳定性的同时,部分减低了晶体的声表面波机电耦合系数,略提高了晶体的声表面波相速度,减小了能流角。综合来看,其机电耦合系数仍明显高于传统压电材料,而声表面波相速度则明显低于传统压电材料。这有利于增加声表面波器件的带宽并减小器件尺寸。因此铌铟酸铅-铌镁酸铅-钛酸铅单晶具有较优异的声表面波性能和较好的温度稳定性。     

Isoelectronic Oxygen Centers and Conductivity of CdS Crystals Compared with PbS Crystals

The influence of oxygen on the electrical properties of PbS are well known. The goal of this study is to compare and reveal this phenomenon in CdS(O) single crystals, which we have studied in detail previously. The experiments are performed for CdS single crystals with a known oxygen concentration, deviation from stoichiometry, and definite set of intrinsic point defects. They allow us to confirm the results described for PbS and clarify their nature. It is shown that the phenomenon is based on the capture of free charge carriers— electrons—by acceptor-like isoelectronic O_S centers with the subsequent formation of associates having a complex structure. Previous conclusions on the dissolution mechanism of oxygen in CdS with deviations from stoichiometry are confirmed. Variations in the electrical properties in oxygen-activated PbS(O), similarly to CdS(O), showed that isoelectronic oxygen centers O_S are present in lead sulfide.     

Structural and Thermoelectric Properties of Bi1−x Sb x Nanoalloys Prepared by Mechanical Alloying

Bi_1?x Sb _x nanoparticles were prepared by mechanical alloying and compacted using different techniques. The influence of the composition as well as the pressing conditions on the thermoelectric performance was investigated. A strong dependence of the thermoelectric properties on the composition was found, which deviates from the behavior of single crystals. The results indicate a significant change in the band structure of the material induced by the reduced size. The influence of the pressing conditions on the thermoelectric properties also showed composition dependence. The results show that the compacting method has to be chosen carefully.     

Degradation of mercuric iodide crystals on aging

Mercuric iodide single crystals were grown and characterized by studying their spectral response of photoconductivity, thermally stimulated current, dielectric constant and di-electric loss as a function of frequency. The as-grown crystals have high resistivity, good photo-sensitivity, low dielectric constant and loss at low frequencies, etc. On aging, the crystals show degradation in their properties when they were stored in air, whereas the crystals stored in an iodine chamber do not exhibit any degradation. The degradation of the properties have been interpreted in terms of surface evaporation of HgI₂ and consequently formation of a surface layer rich in mercuric atoms. The effect of a dc bias on aged (degraded) samples shows restoration of the properties. The results could be interpreted in terms of polarization of mobile defects and formation of space charge layers which enhance a high internal field in the crystals, hence the restoration of the properties.     

Optical properties of nanocolumnar ZnO crystals

Oriented nanocolumnar ZnO single crystals were prepared by the electrodeposition technique on conducting glass substrates by using different growth parameters. A factorial design at two levels of three growth parameters such as current density, exposition time and temperature of the bath has been used to study their influence on the height of ZnO columns. The average height of the Zn nanocolumns was obtained by means of atomic force microscopy. X-ray diffraction and scanning electron microscope were used to characterize the morphology of the nanocolumnar ZnO crystals. The optical properties were investigated by means of transmittance and photoluminescence. It was found that further annealing of the electrodeposited samples was necessary in order to achieve good optical properties which are very sensitive to the duration and temperature of the annealing.     

Luminescence of copper-aluminum diselenide

The results of a multifaceted investigation of the luminescence properties of single crystals of copper-aluminum diselenide CuAlSe₂ are presented. The luminescence spectrum of undoped single crystals of this compound with homogeneous composition was found to have a complex structure. The luminescence properties were modified by annealing the compound in various atmospheres. The nature of the radiative transitions in this semiconductor was analyzed. Fiz. Tekh. Poluprovodn. 31, 377–380 (March 1997)     

Crystal growth of aluminum nitride under high pressure of nitrogen

We report on the results of AlN crystal growth at high nitrogen pressure of the order of 1 GPa and temperatures up to 2000 K. Both, needle-like and bulk form of AlN single crystals up to 1 cm and 1 mm, respectively, have been obtained. We discuss the influence of temperature and supersaturation on the habit and morphology of AlN crystals. The crystals were characterized by X-ray diffraction method, scanning electron microscopy (SEM) and energy dispersive X-ray analyser attached to SEM.