Microstructure and Electrical Characteristics of ITO/CuPc/TCNQ/Al and ITO/TCNQ/CuPc/Al Heterojunctions

2011 ◽  
Vol 403-408 ◽  
pp. 5097-5101 ◽  
Author(s):  
Theerasak Juagwon ◽  
Tanakorn Osotchan
Keyword(s):  
Grain Size ◽  
Electrical Characteristic ◽  
Copper Phthalocyanine ◽  
Semiconductor Layer ◽  
Organic Layer ◽  
Measured Temperature ◽  
Electrical Characteristics ◽  
Thermal Evaporation Method ◽  
Alternative Structures ◽  
Cupc Film

Microstructure of heterojunction usually has strong influence on its electrical characteristic. In order to study the effect of microstructure, the layers of copper phthalocyanine (CuPc) and tetracyanoquinodimethane (TCNQ) are deposited on indium tin oxide (ITO) coated glass substrate by thermal evaporation method. The modification of microstructure in the organic semiconductor layer with varied underneath layer is studied in the heterojunction between CuPc and TCNQ. Then the effect on its electrical characteristic is examined between ITO and aluminum (Al) electrodes in these alternative structures. By determining the microstructure by atomic force microscope (AFM), the CuPc and TCNQ thin films provide very tiny and large grain, respectively. These large grains in TCNQ thin film connect into line pattern probably due to the slow grain growth. Therefore the CuPc film is deposited on this TCNQ layer, the larger gain size of CuPc film can be achieved. However, the TCNQ layer grown on top of tiny grain of CuPc exhibits relatively small grain size. The variation of X-ray diffraction (XRD) peaks of these alternative structures support the microstructure extracted from AFM image very well. The optical absorption of these various structures exhibits the combination of absorption peaks from each layer. The electrical characteristics of these structures strongly depend on junction between ITO electrode and organic layer. The heterojunction structures of ITO/CuPc/Al and ITO/CuPc/TCNQ/Al show rectifier characteristics while the structures of ITO/TCNQ/Al and ITO/TCNQ/CuPc/Al exhibit similar IV characteristic for both polarities. However the effect of larger grain size in TCNQ layer leads to very much higher current than those other structures. By measuring current down to temperature of 50 K, it is found that the structures with rectifier junction indicate the current decreasing more than five orders of magnitude while the junctions with no rectifier characteristic exhibit only slightly current change even the measured temperature is reduced to very low temperature.

scholarly journals Photoresponse characteristics from vacuum deposited thin film of copper phthalocyanine: dependence on grain size

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Arka Mandal ◽  
◽  
Biswanath Mukherjee
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Substrate Temperature ◽  
Copper Phthalocyanine ◽  
High Vacuum ◽  
Single Layer ◽  
Optical Power ◽  
Force Microscopy ◽  
Cupc Film ◽  
Layer Thin Film

An organic photodetector (PD) is fabricated with single layer thin film of copper phthalocyanine (CuPc) on glass substrate. The thermal deposition of CuPc film on the substrate was realized under high vacuum and at different substrate temperature (room temperature, 40 ◦C, 70 ◦C, 100 ◦C). The comparison of photoresponse characteristics of CuPc thin film deposited under different conditions showed good improvement with increase in the substrate temperature, and the best performances being observed for the film deposited at substrate temperature of 100 ◦C. The thin film of CuPc characterized through X-ray diffraction (XRD) spectroscopy and atomic force microscopy (AFM) clearly indicated that with increase in substrate temperature, the grain size of CuPc film increased, which improved the crystallinity and hence the photoconductivity of the device. The CuPc thin film based PD displayed stable and reproducible photoswitching characteristics under white light irradiation, with photocurrent modulation by varying in input optical power. The highest photo to dark current ratio and responsitivity of the devices was calculated to be, ca. 6.5 and 7.1 mA-W−1 at low optical power, ca. 14.5 mW-cm−2.

Structural and Electrical Characterization of Shaped Beam Laser Recrystallized Polysilicon on Amorphous Substrates

1981 ◽  
Vol 4 ◽  
Author(s):  
T. J. Stultz ◽  
J. F. Gibbons
Keyword(s):  
Grain Size ◽  
Electrical Characterization ◽  
Grain Structure ◽  
Electrical Characteristics ◽  
Shaped Beam ◽  
Beam Laser ◽  
Cw Laser ◽  
Amorphous Substrates ◽  
Circular Beam

ABSTRACTStructural and electrical characterization of laser recrystallized LPCVD silicon films on amorphous substrates using a shaped cw laser beam have been performed. In comparing the results to data obtained using a circular beam, it was found that a significant increase in grain size can be achieved and that the surface morphology of the shaped beam recrystallized material was much smoother. It was also found that whereas circular beam recrystallized material has a random grain structure, shaped beam material is highly oriented with a <100> texture. Finally the electrical characteristics of the recrystallized film were very good when measured in directions parallel to the grain boundaries.

STUDY OF ELECTRICAL CHARACTERISTIC FOR 50NM AND 10NM SOI BODY THICKNESS IN MOSFET DEVICE

2015 ◽  
Vol 77 (21) ◽  
Author(s):  
M.N.I.A Aziz ◽  
F. Salehuddin ◽  
A.S.M. Zain ◽  
K.E. Kaharudin
Keyword(s):  
Thin Film ◽  
Electrical Characteristic ◽  
Silicon On Insulator ◽  
Electrical Characteristics ◽  
Short Channel ◽  
Doping Density ◽  
Soi Mosfet ◽  
Buried Oxide ◽  
Soi Technology ◽  
Better Than

Silicon-on-insulator (SOI) technology is an effective approach of mitigating the short channel effect (SCE) problems. The SOI is believed to be capable of suppressing the SCE, thereby improving the overall electrical characteristics of MOSFET device. SCE in SOI MOSFET is heavily influenced by thin film thickness, thin-film doping density and buried oxide (BOX) thickness. This paper will analyze the effect of BOX towards SOI MOSFET device. The 50nm and 10nm thickness of buried oxide in SOI MOSFET was developed by using SILVACO TCAD tools, specifically known as Athena and Atlas modules. From the observation, the electrical characteristic of 100nm thickness is slightly better than 50nm and 10nm. It is observed that the value drive current of 10nm and 100nm thickness SOI MOSFET was 6.9% and 11% lower than 50nm respectively, but the overall 50nm is superior. However, the electrical characteristics of 10nm SOI MOSFET are still closer and within the range of ITRS 2013 prediction.

scholarly journals Electrical and Structural Characteristics of Excimer Laser-Crystallized Polycrystalline Si1−xGex Thin-Film Transistors

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1739 ◽  
Author(s):  
Kyungsoo Jang ◽  
Youngkuk Kim ◽  
Joonghyun Park ◽  
Junsin Yi
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Energy Density ◽  
Excimer Laser ◽  
Density Of States ◽  
Silicon Germanium ◽  
Structural Characteristics ◽  
Thin Film Transistor ◽  
Electrical Characteristics ◽  
Starting Point

We investigated the characteristics of excimer laser-annealed polycrystalline silicon–germanium (poly-Si1−xGex) thin film and thin-film transistor (TFT). The Ge concentration was increased from 0% to 12.3% using a SiH4 and GeH4 gas mixture, and a Si1−xGex thin film was crystallized using different excimer laser densities. We found that the optimum energy density to obtain maximum grain size depends on the Ge content in the poly-Si1−xGex thin film; we also confirmed that the grain size of the poly-Si1−xGex thin film is more sensitive to energy density than the poly-Si thin film. The maximum grain size of the poly-Si1−xGex film was 387.3 nm for a Ge content of 5.1% at the energy density of 420 mJ/cm2. Poly-Si1−xGex TFT with different Ge concentrations was fabricated, and their structural characteristics were analyzed using Raman spectroscopy and atomic force microscopy. The results showed that, as the Ge concentration increased, the electrical characteristics, such as on current and sub-threshold swing, were deteriorated. The electrical characteristics were simulated by varying the density of states in the poly-Si1−xGex. From this density of states (DOS), the defect state distribution connected with Ge concentration could be identified and used as the basic starting point for further analyses of the poly-Si1−xGex TFTs.

Preparation and Characterization of Zn-Se Bilayer Structure

2007 ◽  
Vol 31 ◽  
pp. 153-157
Author(s):  
M. Singh ◽  
J.S. Arora ◽  
Kamlendra Awasthi ◽  
R. Nathawat ◽  
Y.K. Vijay
Keyword(s):  
Grain Size ◽  
Annealing Temperature ◽  
Hexagonal Structure ◽  
Scattering Data ◽  
Bilayer Structure ◽  
X Ray Diffraction ◽  
Thermal Evaporation Method ◽  
Rutherford Back Scattering ◽  
Back Scattering

The Zn-Se bilayer structure prepared using thermal evaporation method at pressure 10-5 Torr. These films annealed in the vacuum for two hours on different constant temperatures. The optical band gap was found to be varying with annealing temperature due to removal of defects and increase in grain size. It was also observed by the X-ray diffraction pattern the grain size of the film increase with annealing temperature. The lattice constant of hexagonal structure of these films is found to be a =b=4.42Å and c=5.68Å. The dominant peaks to be at 23.2°,28° and 43.9° having values (100), (002) and (111) respectively. The Rutherford back scattering data of these films confirmed the mixing of elements with time.

Study of Nonlinear Current-Voltage Characteristic of Semiconductor Ceramic by the Method of Tilted Energy Band

2014 ◽  
Vol 941-944 ◽  
pp. 547-550
Author(s):  
Chao Fang ◽  
Liang Yan Chen
Keyword(s):  
Grain Size ◽  
Energy Band ◽  
Breakdown Field ◽  
Electrical Characteristics ◽  
Current Voltage ◽  
Non Linear ◽  
Semiconducting Ceramics ◽  
Current Voltage Characteristics ◽  
Effective Carrier ◽  
Grain Boundary Barrier

A analytic method for the calculation of the electrical characteristics of semiconducting ceramics is suggested. This paper put forward the concept of effective carrier concentration. Electrical characteristics under extra electric field have been calculated by the method of tilted energy band. The non-linear current-voltage characteristics with different grain sizes has been obtained. The results pointed out that the current-voltage characteristics divide into three regions: Linear region before breakdown field, nonlinear region near breakdown field and upturn region after breakdown field; The grain boundary barrier leads to the strong non-linear characteristics, which has nothing to do with the grain size. With the grain size decreasing, the breakdown field increases. The results are compared with experimental data.

Properties of Delta Doped Al0.25Ga0.75N and GaN Epitaxial Layers

2002 ◽  
Vol 743 ◽  
Author(s):  
Jeffrey S. Flynn ◽  
Leah G. Wallace ◽  
Joe A. Dion ◽  
Edward L. Hutchins ◽  
Helder Antunes ◽  
...  
Keyword(s):  
Room Temperature ◽  
Semiconductor Layer ◽  
Electrical Characteristics ◽  
Group Iii ◽  
Sapphire Substrates ◽  
Delta Doping ◽  
Sheet Charge ◽  
Nitride Layers ◽  
Secondary Ion ◽  
Fixed Period

ABSTRACTDelta doping (paused growth doping) was investigated as an alternative to uniformly distributing the dopant in the nitride semiconductor layer. In this work, delta doped layers were produced in MOVPE-grown AlGaN and GaN layers at a susceptor temperature of 1220°C by turning off the group III precursors (TMG and TMA) and introducing into the reactor a silicon precursor Si2H6 (disilane) for a fixed period (pause time) before growth was restarted. The compositional and electrical properties as a function of aluminum content and dopant flux were investigated for nitride layers on 2 inch c-plane sapphire substrates. Secondary ion mass spectroscopy (SIMS) measurements revealed a sharp silicon peak with a FWHM of 5.7 ± 0.6 nm for an Al0.25Ga0.75N sample and 10.0 ± 0.6 nm for a GaN sample with sheet charges of 7.9×1012 cm−2 and 9.9×1012 cm−2,respectively. Room temperature Hall mobility as high as 265 cm2 V−1s−1 for a sheet charge 7.9×1012 cm−2 was demonstrated for delta doped Al0.25Ga0.75N layers, but the mobility enhancement saturated and then decreased with increasing sheet charge. Room temperature sheet charge increased with increasing dopant flux for delta-doped AlGaN and GaN layers. Sheet charge density as high as 2.2×1013 cm−2 and 1.3×1013 cm−2 was measured at room temperature for Al0.25Ga0.75N and GaN delta doped layers, respectively. Under identical doping conditions, the Hall sheet charge of the delta doped Al0.25Ga0.75N layer was approximately half as large as GaN layers. The impurity and electrical characteristics of the delta doped layers are further discussed.

Copper Phthalocyanine Single-crystal Field-effect Transistors Stable Above 100°C

2006 ◽  
Vol 937 ◽  
Author(s):  
Koichi Yamada ◽  
Jun Takeya ◽  
Kunji Shigeto ◽  
Kazuhito Tsukagoshi ◽  
Yoshinobu Aoyagi ◽  
...  
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Crystal Field ◽  
Field Effect ◽  
Copper Phthalocyanine ◽  
Field Effect Transistors ◽  
Measured Temperature ◽  
Field Effect Mobility ◽  
Crystal Field Effect ◽  
Activation Type

ABSTRACTIntrinsic charge transport of copper phthalocyanine single-crystal field-effect transistors is measured as function of temperature up to above 100°C. The conduction of the accumulated carriers shows hopping-type transport, so that the field-effect mobility increases with temperature following activation-type temperature dependence throughout the measured temperature region. Due to excellent material stability at the high temperature, the mobility values are precisely reproduced after the heat cycles.

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