Optoelectronics – Devices and Applications

Optoelectronics - Devices and Applications is the second part of an edited anthology on the multifaced areas of optoelectronics by a selected group of authors including promising novices to experts in the field. Photonics and optoelectronics are making an impact multiple times as the semiconductor revolution made on the quality of our life. In telecommunication, entertainment devices, computational techniques, clean energy harvesting, medical instrumentation, materials and device characterization and scores of other areas of R&D the science of optics and electronics get coupled by fine technology advances to make incredibly large strides. The technology of light has advanced to a stage where disciplines sans boundaries are finding it indispensable. New design concepts are fast emerging and being tested and applications developed in an unimaginable pace and speed. The wide spectrum of topics related to optoelectronics and photonics presented here is sure to make this collection of essays extremely useful to students and other stake holders in the field such as researchers and device designers

异质结能带边不连续性的第一性原理计算

【中文摘要】 本文根据异质结界面两侧的平均键能相互“对齐”的研究结果,以平均键能作为参考能级,采用改进计算效率的LMTO-ASA能带从头计算方法,计算了10种异质结的价带边不连续ΔE_v值,所得结果与更严格的第一性原理的界面自洽计算的结果非常一致,而且计算量比界面自洽方法要小得多,便于在中型计算机条件下推广应用.国家和福建省自然科学基

A LATTICE INVERSION METHOD TO CONSTRUCT THE ALLOY PAIR POTENTIAL FOR THE EMBEDDED-ATOM METHOD

The lattice inversion method is used to construct the pair potential between a pair of unlike atoms for Cu-Au and Cu-Pd intermetallic compounds within the framework of Johnson's analytical model of the embedded-atom method. Compared with previous treatises, the alloy potential obtained by the present method is based on the LI(2) superstructures Cu3Au and Cu3Pd as references so that the usual assumption that the pair potential between distinct atoms is a function of monatomic pair potentials is cancelled. The alloy potentials from inversion fall in with those from the average schemes of Foiles et al and Johnson in the short range but show deviation in the long range. The present method is used to solve the considerable disagreements of Johnson's calculations for the dilute-limit heats of solution and the phase stabilities of the intermetallic compounds of palladium with noble metals. While the overall degree of agreement is substantially improved, it is not good in some cases, nor is the phonon spectrum of gold

Optimization Design of Top Contact Metallization of Concentrator Solar Cells

【中文摘要】 对聚光型太阳电池表面栅极图形进行优化设计。对组成太阳电池表面栅电极的图形最小单元的各种功率损失进行了详细分析,得到了最佳栅电极间距的递推公式。优化计算了各种宽度的次栅之间的间距,并得到了相对应的功率损失比例。电极和半导体接触良好时,当次栅间距小于最佳值,电极的遮挡对于功率损失影响最大;而当次栅间距大于最佳值时,太阳电池体材料输运功率损失和次栅电极电流输运功率损失开始成为主要原因。对于高倍聚光型太阳电池来说,次栅电极的厚度相对要求厚一些。计算及分析结果可应用于聚光型太阳电池电极的设计中。 【英文摘要】 An optimum grid pattern of the concentrator solar cell top contact metallization was designed. Several power-loss mechanisms of the smallest element were analyzed detailedly. The optimum grid spacing recursion formula was deduced. The optimum grid spacing and the power-loss for the grids of different width were calculated. The shadowing loss was the biggest loss when the grid spacing was narrower than the optimum one if ohmic contact was very well. Otherwise,the current transporting power losses of the grid...中国博士后科学基金面上资助项

LATTICE INVERSION METHOD AND AB-INITIO PAIR POTENTIALS IN CU-AG, CU-AU AND AG-AU INTERMETALLIC COMPOUNDS

The lattice inversion method is used to construct ab initio pair potentials in the noble-metal alloy systems Cu-Ag, Cu-Au and Ag-Au from the elemental crystals and a L1(2) binary superstructure as references. Also, we present an alternative method for the determination of the three-dimensional Mobius functions by using the Kronecker expansion

A generalized integral fluctuation theorem for general jump processes

Using the Feynman-Kac and Cameron-Martin-Girsanov formulas, we obtain a generalized integral fluctuation theorem (GIFT) for discrete jump processes by constructing a time-invariable inner product. The existing discrete IFTs can be derived as its specific cases. A connection between our approach and the conventional time-reversal method is also established. Different from the latter approach that was extensively employed in existing literature, our approach can naturally bring out the definition of a time-reversal of a Markovian stochastic system. Additionally, we find the robust GIFT usually does not result into a detailed fluctuation theorem

A Two-dimensional Analytical Model to GAT′s Gate Shielding Effect

【中文摘要】 建立了 GAT器件集电结耗尽层电位分布和电场分布的二维解析模型 ,定量研究了GAT的栅屏蔽效应的解析表达式 ,并借助计算机对栅屏蔽效应给以证实。该模型可供优化设计双极型高频、高压、低饱和压降功率器件参考。 【英文摘要】 A two dimensional analytical model of the electric potential and field distribution in GAT’s collector depletion space in the cut off state is derived for the first time.The formula for GAT’s gate shielding effect is derived and the gate shielding effect is proved by aid of computer quantitatively.This model will provide assistance to the optimal design of bipolar power transistor with high frequency and high breakdown voltage.国家自然科学基金( No.69896260 -06); 国家高技术研究发展计划( 863-715-010

AVERAGE BONDING ANTIBONDING ENERGY AT SEMICONDUCTOR HETEROJUNCTIONS AND ITS APPLICATION TO CALCULATING THE VALENCE BAND OFFSET

In this paper, the alignment of the average bonding-antibonding energy E(m) between the two sides of heterojunctions and other relevant behaviour have been investigated. This study is based on the peculiarity of the atomic sphere approximation in the linear muffin-tin orbital band-structure calculation. Using E(m) as an energy reference, we have determined the valence band offset DELTAE(v)-values for 16 heterojunctions. The calculated results are in excellent agreement with the available experimental data, and the computational effort required is very small

THE INTERFACE CHARGE-TRANSFER AND INTERNAL ELECTRIC-FIELDS IN COMMON-ANION AND NON-COMMON-ION SUPERLATTICES

The hetero-interface of the common-anion superlattice (SL) (GaAs)3(AlAs)3(001) is on the As atomic plane, while that of the non-common-ion SL (AlAs)3(GeGe)3(001) is between the two atomic planes of As and Ge or of Ge and Al. In this paper, the self-consistent electronic structure calculation is reported for the two structures. The frozen-shape approach is used to determine the average bond energy and the valence band maximum in each molecular layer of the SL, and to investigate the relation between the interface structure and the internal electrical field. The results show that a large internal electric field exists in the non-common-ion SL but does not in the common-anion SL

Valence-band offset at ALxGa1-xAs/GaAs:Application of average-bond-energy theory in conjunction with the cluser expansion method

We suggest a theoretical method for the determination of valence-band offsets at alloy-type heterojunctions that is based on average-bond-energy theory in conjunction with a cluster expansion method. The application of this method to AlxGa1-xAs/GaAs produces results in very good agreement with relevant experimental data