A New Approach to Growth of Bulk Zno Crystals for Wide Bandgap Applications

1998 ◽  
Vol 512 ◽  
Author(s):  
G. Agarwal ◽  
J. E. Nause ◽  
D. N. Hill
Keyword(s):  
Zinc Oxide ◽  
Single Crystal ◽  
Low Cost ◽  
Large Diameter ◽  
Wide Band ◽  
Wide Bandgap ◽  
Wide Band Gap ◽  
New Approach ◽  
Zinc Oxide Powder ◽  
Zno Single Crystal

ABSTRACTA novel technique was used to melt zinc oxide powder. This techniques involves the pressurized RF induction heating of ZnO, contained in a water-cooled crucible. The ability to obtain a pool of molten ZnO enables the pulling of large diameter ZnO crystals using conventional melt growth processes. Centimeter-sized crystals were obtained in the preliminary experiments by cooling the ZnO melt. These crystals were analyzed for crystalline perfection and stoichiometry using x-ray diffiraction and photoluminescence. The semiconductor properties of these crystals were also measured. This technology can potentially provide large, low cost ZnO single crystal wafers for use in the fabrication of GaN blue diodes and blue lasers, high temperature / high power FETs, as well as homoepitaxy of ZnO wide band-gap devices. Single crystal zinc oxide also has potential application in the piezoelectric device market.

Mechanisms of Excimer Laser Ablation of Wide Band-Gap Materials: the Role of Defects in Single Crystal MgO

1992 ◽  
Vol 285 ◽  
Author(s):  
J. T. Dickinson ◽  
L. C. Jensen ◽  
R. L. Webb ◽  
M. L. Dawes ◽  
S. C. Langford
Keyword(s):  
Laser Ablation ◽  
Single Crystal ◽  
Wide Band ◽  
Wide Bandgap ◽  
Film Deposition ◽  
Wide Band Gap ◽  
Defect Production ◽  
Materials Analysis ◽  
Wide Bandgap Materials ◽  
Bandgap Materials

ABSTRACTLaser ablation has important applications in surface modification, materials analysis, and thin film deposition. We have been examining the details of processes that lead to the emission and formation of particles (atomic/molecular ground state neutrals, excited neutrals, tions, electrons) when wide band gap materials are irradiated with pulsed UV laser light. Etching and deposition of wide bandgap materials is of particular interest due to their excellent insulating and optical properties. Our studies bear directly on achieving control of emission intensities and particle characteristics for use in film deposition and materials analysis. In model wide bandgap materials such as single crystal alkali halides and MgO (nominally transparent materials), exposure to repeated pulses of 248 nm excimer laser radiation of a few J/cm2 results in substantial interaction including extensive biaxial deformation and cleavage. Significant surface heating also occurs, consistent with strong free-carrier/laser interactions. We present strong evidence that achieving intense emission of atomic, molecular, and ionic particles actually depends on point defect production by laser-induced deformation and fracture. Defect production via dislocation motion yields orders of magnitude increases in laser vaporization of these wide bandgap materials, including cluster ion formation. The dependence of the laser-material interaction on dislocation density and mobility, as well as point defect density, suggests several novel strategies for the enhancing the ablative response or preventing laser damage.

Application of Wide Band Gap Semiconductors to Increase Photocurrent in a Protein Based Photovoltaic Device

2012 ◽  
Vol 1414 ◽  
Author(s):  
Arash Takshi ◽  
Houman Yaghoubi ◽  
Daniel Jun ◽  
Rafael Saer ◽  
Ali Mahmoudzadeh ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Indium Tin Oxide ◽  
Wide Band ◽  
Photocurrent Density ◽  
Wide Bandgap ◽  
Semiconducting Materials ◽  
Wide Band Gap ◽  
Electron Hole ◽  
New Approach ◽  
Wide Band Gap Semiconductors

ABSTRACTReaction centers (RCs) from natural photosynthetic cells are photoactive proteins, which generate electron-hole pairs in presence of light. In a new approach presented in this work, a solution of suspended RCs with mediators has been applied as the electrolyte to build electrochemical based photovoltaic (PV) devices. In this approach, the mediators transfer charges from the RCs to the electrodes (indirect charge transfer). Various metallic and wide bandgap semiconducting materials, including Carbon, Au, Indium Tin Oxide (ITO), SnO2, WO3, have been tested as the electrodes. Among all WO3, which is a semiconductor, have shown the largest photocurrent density with an amount of ∼5.1 μA/cm2. The results show that the material of the electrode can affect the rates of the reactions in the cell. Choosing an appropriate material for the electrode, the charge transfer from the mediators to the electrode would be rectified to achieve a large photocurrent.

PROPERTIES OF AMORPHOUS GAN GROWN ON SILICON

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1086-1090 ◽  
Author(s):  
Z. HASSAN ◽  
K. IBRAHIM ◽  
M. E. KORDESCH ◽  
W. HALVERSON ◽  
P. C. COLTER
Keyword(s):  
Electron Cyclotron Resonance ◽  
Low Cost ◽  
Photovoltaic Effect ◽  
Large Diameter ◽  
Chemical Vapor ◽  
Wide Band ◽  
Wide Band Gap ◽  
Force Microscopy ◽  
Ecr Plasma ◽  
Potential Alternative

The success of crystalline GaN as an optical and electronic material has motivated an enormous effort to explore all aspects of the material. Little is known and reported about the amorphous phase of this semiconducting wide band gap material. In this paper, we report on the properties of amorphous GaN (a-GaN) grown on p-Si at 443K using electron cyclotron resonance (ECR) plasma-assisted metalorganic chemical vapor deposition (MOCVD). Silicon is a potential alternative to sapphire due to its high quality and readily available as a large diameter and low cost substrates. The film was analyzed by a variety of methods, including scanning electron microscopy (SEM), atomic force microscopy (AFM) and x-ray diffraction (XRD). The current-voltage characteristics of a-GaN/Si heterojunction were measured from room temperature to 363K. Rectification behavior and photovoltaic effect were observed for this anisotype heterojunction. The electrical characteristics of Ni Schottky barriers on a-GaN were also investigated.

Rare Earth Doped Zinc Oxide Nanowires

2008 ◽  
Vol 8 (1) ◽  
pp. 244-251 ◽  
Author(s):  
S. Geburt ◽  
D. Stichtenoth ◽  
S. Müller ◽  
W. Dewald ◽  
C. Ronning ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Rare Earth ◽  
Thermal Quenching ◽  
Wide Band ◽  
Wide Band Gap ◽  
Oxide Nanowires ◽  
Defect Sites ◽  
Optical Activation ◽  
Re Elements ◽  
Rare Earth Doped

Zinc oxide (ZnO) nanowires were grown via thermal transport and subsequently doped with different concentrations of Tm, Yb, and Eu using ion implantation and post annealing. High ion fluences lead to morphology changes due to sputtering; however, freestanding nanowires become less damaged compared to those attached to substrates. No other phases like rare earth (RE) oxides were detected, no amorphization occurs in any sample, and homogeneous doping with the desired concentrations was achieved. Photoluminescence measurements demonstrate the optical activation of trivalent RE-elements and the emission of the characteristic intra-4f-luminescence of the respective RE atoms, which could be assigned according to the Dieke-diagram. An increasing RE concentration results into decreasing luminescence intensity caused by energy transfer mechanisms to non-radiative remaining implantation defect sites. Furthermore, low thermal quenching was observed due to the considerable wide band gap of ZnO.

scholarly journals Epitaxial Growth of a Single-Crystal Hybridized Boron Nitride and Graphene Layer on a Wide-Band Gap Semiconductor

2015 ◽  
Vol 137 (21) ◽  
pp. 6897-6905 ◽  
Author(s):  
Ha-Chul Shin ◽  
Yamujin Jang ◽  
Tae-Hoon Kim ◽  
Jun-Hae Lee ◽  
Dong-Hwa Oh ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Single Crystal ◽  
Band Gap ◽  
Epitaxial Growth ◽  
Graphene Layer ◽  
Wide Band ◽  
Wide Band Gap

Novel sputtering method to obtain wide band gap and low resistivity in as-deposited magnesium doped zinc oxide films

2019 ◽  
Vol 104 ◽  
pp. 104646 ◽  
Author(s):  
M. Loeza-Poot ◽  
R. Mis-Fernández ◽  
I. Rimmaudo ◽  
E. Camacho-Espinosa ◽  
J.L. Peña
Keyword(s):  
Zinc Oxide ◽  
Band Gap ◽  
Oxide Films ◽  
Wide Band ◽  
Wide Band Gap ◽  
Low Resistivity ◽  
Zinc Oxide Films

scholarly journals Wide band gap kesterite absorbers for thin film solar cells: potential and challenges for their deployment in tandem devices

2019 ◽  
Vol 3 (9) ◽  
pp. 2246-2259 ◽  
Author(s):  
Bart Vermang ◽  
Guy Brammertz ◽  
Marc Meuris ◽  
Thomas Schnabel ◽  
Erik Ahlswede ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Band Gap ◽  
Wide Band ◽  
Wide Bandgap ◽  
Thin Film Solar Cells ◽  
Wide Band Gap ◽  
Tandem Solar Cells

This study describes the potential and challenges involved with the use of wide bandgap kesterite absorbers in tandem solar cells.

Laser ablation of wide band-gap materials: The role of defects in single crystal MgO

1993 ◽  
Author(s):  
J. T. Dickinson ◽  
L. C. Jensen ◽  
R. L. Webb ◽  
S. C. Langford
Keyword(s):  
Laser Ablation ◽  
Single Crystal ◽  
Band Gap ◽  
Wide Band ◽  
Wide Band Gap

Challenges and State-of-the-Art of Oxides on SiC

2000 ◽  
Vol 640 ◽  
Author(s):  
Lori Lipkin ◽  
Mrinal Das ◽  
John Palmour
Keyword(s):  
Single Crystal ◽  
Band Gap ◽  
High Voltage ◽  
State Of The Art ◽  
Wide Band ◽  
High Current ◽  
Power Devices ◽  
Wide Band Gap ◽  
Single Crystal Sic ◽  
Lower Temperature

ABSTRACTSingle crystal SiC is a wide band-gap semiconductor with material characteristics that make it quite suitable for high voltage and high current applications. However, these devices are currently limited by their passivation. Significant improvements have been made with oxides on SiC. The most notable oxide processes are the re-oxidation anneal, a stacked ONO dielectric, and nitridation using an NO or N2O anneal. Additional improvements in lateral MOSFET mobility have been achieved using a surface channel implant, and lower temperature implant activation anneals. However, the passivation remains a significant limitation for SiC power devices.

Wide Band Gap Semiconductor Technology for Energy Efficiency

2016 ◽  
Vol 858 ◽  
pp. 797-802 ◽  
Author(s):  
Anant Agarwal ◽  
Woong Je Sung ◽  
Laura Marlino ◽  
Pawel Gradzki ◽  
John Muth ◽  
...  
Keyword(s):  
Cost Reduction ◽  
Wide Band ◽  
Wide Bandgap ◽  
Department Of Energy ◽  
Semiconductor Technology ◽  
Power Devices ◽  
Wide Band Gap ◽  
Efficient Energy ◽  
Greenhouse Gas Reduction ◽  
Silicon Power Devices

The attributes and benefits of wide-bandgap (WBG) semiconductors are rapidly becoming known, as their use in power electronics applications continues to gain industry acceptance. However, hurdles still exist in achieving widespread market acceptance, on a par with traditional silicon power devices. Primary challenges include reducing device costs and the expansion of a workforce trained in their use. The Department of Energy (DOE) is actively fostering development activities to expand application spaces, achieve acceptable cost reduction targets and grow the acceptance of WBG devices to realize DOEs core missions of more efficient energy generation, greenhouse gas reduction and energy security within the U.S. This paper discusses currently funded activities and application areas that are suitable for WBG introduction. A detailed cost roadmap for SiC device introduction is also presented.

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