By Leon Watkins,2014-12-14 12:05
6 views 0

    Champions of technological innovation: The influence of contextual knowledge, role orientation, idea generation, and idea promotion on champion

    emergence Original Research Article

    The Leadership Quarterly

    Innovation and international technology transfer: The case of the Chinese photovoltaic industry Original Research Article

    Energy Policy

    Research Highlights

    ?China has become the world leader in the production of PV cells and modules, but remains far behind industrialized countries in the more upstream segments of the photovoltaic industry. ?International

    technology transfers from industrialized countries to China have taken place through two main channels: the competitive market of manufacturing equipments, and labour mobility. ?Fierce competition between

    equipment manufacturers and public availability of core technology have prevented intellectual property rights from hindering technology transfers towards China. ?As compared with their foreign competitors, Chinese firms file many patents, but of low technical and commercial value. ?Chinese firms' innovation

    is focused on process rather than on products.

    This study examined the role that champions play in the generation and promotion of ideas in the innovation process, and considered the influence of flexible role orientation and contextual knowledge in this process. Content analysis of interview transcripts from 19 matched pairs of champions and nonchampions revealed that flexible role orientation was positively related to idea generation, and contextual knowledge was positively related to packaging ideas for promotion. Idea generation was positively related to promoting ideas through informal and formal channels. Finally, in comparison with nonchampions, champions demonstrated more enthusiastic support for new ideas, tied the innovation to a greater variety of positive organizational outcomes, and used informal selling processes more often during idea promotion.

    Article Outline

    1. Introduction

    1.1. Idea generation and champion emergence

    1.2. Idea promotion and champion emergence

    1.3. Idea generation and idea promotion

    1.4. Flexible role orientation and idea generation

1.5. Contextual knowledge and idea promotion

    2. Method

    2.1. Description of innovations

    2.2. Sample

    2.3. Procedure

    2.4. Identification of champions and nonchampions

    2.5. Content analysis

    2.5.1. Coding themes

    2.5.2. Procedure

    2.6. Data analysis

    3. Results

    3.1. Paired sample t tests

    3.2. PLS analysis: test of the measurement model

    3.3. PLS analysis: test of the hypotheses

    4. Discussion

    4.1. Limitations, future research directions, and practical implications



    Recent progress of molecular organic electroluminescent materials and devices Review Article

    Materials Science and Engineering: R: Reports

    Electroluminescent devices based on organic materials are of considerable interest owing to their attractive characteristics and potential applications to flat panel displays. After a brief overview of the device construction and operating principles, a review is presented on recent progress in organic electroluminescent materials and devices. Small molecular materials are described with emphasis on their material issues pertaining to charge transport, color, and luminance efficiencies. The chemical nature of electrode/organic interfaces and its impact on device performance are then discussed. Particular attention is paid to recent advances in interface engineering that is of paramount importance to modify the chemical and electronic structure of the interface. The topics in this report also include recent

development on the enhancement of electron transport capability in organic materials by doping and the

    increase in luminance efficiency by utilizing electrophosphorescent materials. Of particular interest for the

    subject of this review are device reliability and its relationship with material characteristics and interface

    structures. Important issues relating to display fabrication and the status of display development are

    briefly addressed as well. Article Outline

    1. Introduction

    2. Background

    2.1. Device configuration and operation

    2.2. Materials

    2.3. Device preparation

    2.4. Analytical tools

    2.4.1. Electrical and optical properties

    2.4.2. Metalorganic interfaces

    2.4.3. Carrier mobilities

    3. Molecular organic electroluminescent materials 3.1. Hole-injection materials

    3.2. Hole-transport materials

    3.3. Electron-transport and host emitting materials 3.4. Fluorescent dopants

    3.4.1. Green

    3.4.2. Red

    3.4.3. Blue

    3.5. Triplet emitting materials

    4. Charge injection and transport

    4.1. Interface structures and chemistry

    4.1.1. Energy level alignment

    4.1.2. Interactions at metalorganic interfaces

4.2. Cathodes

    4.2.1. Elemental metals

    4.2.2. Metal alloys and compounds MgAg LiAl Alkali metal compounds/Al

    4.2.3. AlO/Al 23

    4.3. Fluoride/Al

    4.3.1. LiF/Al Bilayer cathode Composite cathodes

    4.3.2. CsF

    4.3.3. Mechanisms Shift of light-emitting zones Tunneling and reduction in gap states Interfacial dipoles Lowering Al work function in the presence of water molecules Chemical reaction in the presence of water molecules Dissociation of LiF in the coexistence of Alq, LiF and Al 34.3.4. LiF/Al and CsF/Al on conjugated polymers 4.4. Anodes

    4.4.1. Surface treatments of ITO Acid and base treatments SAMs Plasma treatments

    4.4.2. Buffer layers between ITO and HTL CuPc Platinum Carbon SiO and SiN 234

4.4.3. Non-ITO anodes Fluorine-doped tin oxide Al-doped zinc oxide Transparent conductive oxides (TCO) 4.5. Carrier transport

    4.5.1. Limiting factors in electrical properties 4.5.2. Currentvoltage characteristics 4.5.3. New electron-transport materials 4.5.4. Doping Doping in ETLs Doping in HTLs

    5. Quantum efficiency

    5.1. Phosphorescent OLEDs 5.1.1. Red emission

    5.1.2. Green emission

    5.1.3. Blue emission

    5.1.4. Energy transfer from triplets to singlets 5.1.5. Operational stability

    5.2. Optical coupling

    5.2.1. General consideration

    5.2.2. Reduction in internal optical loss Microcavity Shaped substrates Silica microspheres Silica aerogel

    6. Reliability

    6.1. Operational stability

    6.1.1. Anode contacts

    6.1.2. Excited state reactions

    6.1.3. Crystallization Self-heating in operation Thermal stability

    6.1.4. Quenching by Alq cations 3

    6.1.5. Mobile ionic impurities

    6.2. Non-emissive sites

    6.2.1. High local field

    6.2.2. Reaction of cathodes with moisture 7. OLED displays

    7.1. Displays on glass

    7.1.1. Matrix addressing

    7.1.2. Color Color filter Color change media Patterned lateral RGB emitters Commonly used EL materials 7.1.3. Encapsulation

    7.1.4. Thin film transistors

    7.1.5. Technology development Equipment for production Phosphorescent OLED displays Flexible OLED displays 7.2. Displays on Si

    7.2.1. Surface-emitting OLEDs Reversed structures Conventional structures MgAg/ITO transparent cathodes Li-doped organic/ITO transparent cathodes ITO-free transparent cathodes 7.2.2. Color stacked OLEDs

    7.2.3. Microdisplays

8. Summary and outlook



    Preparing business students for co-operation in multi-disciplinary new venture teams: empirical insights from a business-planning course Original Research



A review on photovoltaic/thermal hybrid solar technology Review Article

    Applied Energy

    Physical understanding and technological control of carrier lifetimes in semiconductor materials and devices: A critique of conceptual development, state of the art and applications Review Article

    Progress in Quantum Electronics

    This paper surveys the current understanding of the diverse types of carrier lifetime in semiconductor physics, a fundamental physical parameter determining different terminal properties of semiconductor devices and a vital performance index of the degree of cleanliness of a semiconductor material or fabrication line. According as a recombination or generation mechanism is involved, two primary categories of carrier lifetime have been distinguished, namely, recombination and generation lifetimes. Depending on the recombination process, the recombination lifetime has been sub classified as phonon-assisted Shockley-Read-Hall recombination lifetime, photon-assisted radiative recombination lifetime and Auger recombination lifetime. Further from the viewpoint of injection level, lifetime has been divided into low-level and high-level types. Also, a demarcation has been made between lifetime in bulk semiconductor and lifetime in a region of semiconductor device. Both recombination and generation lifetimes or any of their classes, has been associated with a surface recombination/generation velocity and hence a surface lifetime; the measured lifetime value is the combined effect of the bulk and surface components.

    Quantum-mechanical theories of lifetime have been reviewed. After introduction of the Shockley-Read-Hall (SRH) theory of recombination-generation statistics, the Dhariwal-Kothari-Jain modification, Dhariwal-Landsberg generalization and Landsberg's extension of SRH theory have been

    dealt with. Landsberg-Kousik model of dependence of carrier lifetime on doping concentration has been outlined. Beattie-Landsberg Auger recombination lifetime theory has been briefly treated followed by Auger recombination theory for non-interacting free-particle approximation and then Coulomb-enhanced Auger recombination theory based on the Hangleiter and Häcker quantum-mechanical approach. The correlation of lifetime with device properties such as the current gain of bipolar transistors as well as forward voltage drop, reverse leakage current and switching times of devices like thyristors and insulated gate bipolar transistors has been elucidated. Various lifetime measurement techniques have been discussed. The technological steps for preserving or killing lifetime during semiconductor device fabrication have been presented. Experimental investigations of lifetime for material, unit process/manufacturing line and device characterization have been described, the process-induced influence on carrier lifetime has been explained and the main considerations in the analysis of lifetime results have been pointed out.

    Article Outline

    1. Introduction

    2. Necessity of defining two principal lifetimes in semiconductors: recombination and generation lifetimes

    2.1. Thermodynamic equilibrium and non-equilibrium conditions in a semiconductor

    2.2. The concept of recombination lifetime

    2.3. Recombination lifetime is the average life span of excess carriers

    2.4. The notion of generation lifetime

    3. Lifetimes associated with various recombinationgeneration processes in semiconductors

    3.1. Recombinationgeneration processes in semiconductors

    3.2. Direct, indirect and Auger recombination lifetimes

    3.3. Thermal generation lifetime

    4. Direct recombination lifetime

    5. Indirect recombination lifetime: ShockleyReadHall theory of recombinationgeneration statistics and

    ShockleyReadHall lifetime

    5.1. Kinetics of the recombination process

    5.2. Low-level lifetime

5.3. Alternative form of Eqs. (27) and low-level lifetime

    5.4. High-level lifetime

    5.5. Space-charge generation lifetime

    5.6. Relation between recombination and generation lifetimes

    5.7. Analysis of Eq. (39) and injection level dependence of carrier lifetime

    5.8. Ambipolar lifetime

    6. Modifications of ShockleyReadHall theory

    6.1. Validity of simplified ShockleyReadHall statistics

    6.2. DhariwalKothariJain modification of the ShockleyReadHall theory to include the finite relaxation

    time before the captured electron or hole returns to the ground state

    6.3. DhariwalLandsberg generalization of SRH theory via a simplified truncated recombination (TCR)


    7. Auger recombination lifetime

    7.1. BeattieLandsberg Auger recombination lifetime theory

    7.2. Auger recombination for non-interacting free-particle approximation

    7.3. Coulomb-enhanced Auger recombination: Hangleiter and Häcker quantum-mechanical approach 7.4. Coulomb enhancement of Auger recombination at high injection levels

    7.5. Intrinsic upper limit of carrier lifetime controlling the ultimate performance of semiconductor devices 8. Carrier lifetime variation as a function of injection level, and interpretation of carrier lifetimeinjection level characteristics

    8.1. LandsbergKousik model of dependence of carrier lifetime on doping concentration in

    non-degenerate semiconductors based on ‘freezing-in temperature’ of defects

    8.2. Lifetimeinjection level curves from the combination of different recombination mechanisms 9. Bulk and surface lifetimes: surface recombination and generation velocities

    9.1. Surface recombination velocity and surface recombination lifetime

    9.2. Intricacies of surface recombination

    9.3. Surface generation velocity and surface generation lifetime

    10. Landsberg's extension of SRH theory for semiconductor surface studies and extra carrier effects 10.1. Generalization of SRH recombination statistics for an energy distribution of surface states 10.2. Inclusion of the effect of extra carriers from outside

    11. Dependence of physical parameters of semiconductor devices on lifetime 11.1. Forward current of a diode

    11.2. Open-circuit voltage of a PN junction solar cell

    11.3. Carrier lifetimes in the thermodynamic analysis of efficiencies of laser diodes and solar cells 11.4. Emitter injection efficiency, base transport factor and current gain of a bipolar transistor 11.5. Alphas of constituent PNP and NPN transistors in a thyristor

    11.6. Collectoremitter saturation voltage of a bipolar transistor

    11.7. ON-state voltage drop of a thyristor

    11.8. Forward voltage drop of the IGBT (Insulated gate bipolar transistor) 11.9. Leakage currents of diode, bipolar transistor and thyristor; and power dissipation of CMOS circuits

    11.10. Spreading velocity of a thyristor

    11.11. Switching parameters of devices

    12. Optimization of recombination level for achieving the desired device characteristics 12.1. Small-signal switching devices

    12.2. Power semiconductor devices

    13. Measurement of recombination lifetime

    13.1. Photoconductance decay (PCD)

    13.2. Photoluminescence decay (PLD)

    13.3. Surface Photovoltage (SPV)

    13.4. Open-circuit voltage decay (OCVD)

    13.5. Reverse recovery (RR) of a diode

    14. Measurement of generation lifetime

    14.1. Gate-controlled diode

    14.2. Pulsed MOS capacitor (MOS-C)

    15. Lifetime controlling techniques

    15.1. Influence of deep impurity levels on carrier lifetimes in silicon

    15.2. Techniques of lifetime preservation and enhancement

    15.3. Techniques of lifetime reduction

    15.4. Carrier lifetime spectroscopy

    16. Experimental investigations of lifetime by researchers: applications in material defect analysis,

Report this document

For any questions or suggestions please email