Electrical Studies of ZnO Nanowires and Metal Contacts

2015 ◽  
Vol 1131 ◽  
pp. 3-7
Author(s):  
Sattra Thongma ◽  
Artitsupa Boontan ◽  
Thitikorn Boonkoom ◽  
Kittipong Tantisantisom
Keyword(s):  
Indium Tin Oxide ◽  
Optoelectronic Device ◽  
Metal Electrode ◽  
Zno Nanowires ◽  
Metal Contacts ◽  
Voltage Measurement ◽  
Light Emitting ◽  
Current Voltage ◽  
P Type ◽  
A Current

ZnO nanowires are recently used in optoelectronic devices such as sensors, solar cells, and light emitting diodes due to its unique optical and electrical properties. In such devices, a contact between the ZnO nanowires and a metal electrode exists. Hence understanding electrical characteristic between the ZnO nanowires and a metal electrode can facilitate optoelectronic device design. In this work, ZnO nanowires were grown on Indium Tin Oxide (ITO) substrates using a hydrothermal method. Simple devices using the nanowires sandwiched between the ITO and a metal contact (i.e. Au, Al) were fabricated and characterized by a current-voltage measurement. Moreover, studies on p-n junctions between the ZnO nanowires and p-type polymers, poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) and poly(9,9-dioctylfluorene) (PFO), were also fabricated and characterized. The current-voltage measurement of devices clearly shows the rectifying behavior, which is an important characteristic of diodes.

Improvement of the light output and contact resistance of InGaN-based light-emitting diodes based on tantalum-doped indium tin oxide as p-type electrodes

2010 ◽  
Vol 19 (4) ◽  
pp. 047205 ◽  
Author(s):  
Huang Jun-Yi ◽  
Fan Guang-Han ◽  
Zheng Shu-Wen ◽  
Niu Qiao-Li ◽  
Li Shu-Ti ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Light Emitting ◽  
P Type

Highly Reflective and Low Resistance Indium Tin Oxide/Ag Ohmic Contacts to p-Type GaN for Flip-Chip Light Emitting Diodes

2005 ◽  
Vol 8 (11) ◽  
pp. G320 ◽  
Author(s):  
Woong-Ki Hong ◽  
June-O Song ◽  
Hyun-Gi Hong ◽  
Keun-Yong Ban ◽  
Takhee Lee ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Ohmic Contacts ◽  
Flip Chip ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Low Resistance ◽  
P Type

Electrical Properties of Azo-Ferrocene as Organic Diode

2014 ◽  
Vol 895 ◽  
pp. 505-508
Author(s):  
Siti Athirah Mohamad Jamali ◽  
Hasiah Salleh ◽  
Tei Tagg
Keyword(s):  
Electrical Conductivity ◽  
Bias Voltage ◽  
Indium Tin Oxide ◽  
Single Layer ◽  
Potential Range ◽  
Voltage Measurement ◽  
Slow Increase ◽  
Current Voltage ◽  
Ito Glass ◽  
Single Layer Film

Ferrocene is a well-known electron donor due to its chemical stability and redox behaviour. By introducing azo dye as an acceptor in the system, the characteristics of azo-ferrocene (AF) compound as a semiconductor material have been investigated. A single layer film of AF compound was deposited on an indium tin oxide (ITO) glass substrate by electrochemical method in the potential range of 0.4 V to 0.8 V. Electrical conductivity of the thin film was investigated using a four-point probe and I-V characteristic of the diode was determined via a two-point probe method. AF material showed an average electrical conductivity of 0.246 ± 0.003 Scm-1. The forward current-voltage measurement demonstrated a bias voltage in the range of 0.87 V to 10.0 V, and the backward current-voltage measurement indicated a bias voltage in the range of-0.87 V to-7.0 V. In both forward and backward voltages, the current showed a slow increase beyond the readings of 10.0 V to-7.0 V.

Room temperature electroluminescence from arsenic doped p-type ZnO nanowires/n-ZnO thin film homojunction light-emitting diode

2014 ◽  
Vol 25 (4) ◽  
pp. 1955-1958 ◽  
Author(s):  
Hongwei Liang ◽  
Qiuju Feng ◽  
Xiaochuan Xia ◽  
Rong Li ◽  
Huiying Guo ◽  
...  
Keyword(s):  
Thin Film ◽  
Room Temperature ◽  
Light Emitting Diode ◽  
Zno Nanowires ◽  
Zno Thin Film ◽  
Light Emitting ◽  
P Type

ZnO Nanowire/p-GaN Heterojunction LEDs

2007 ◽  
Vol 1018 ◽  
Author(s):  
Heiko O. Jacobs ◽  
Jesse Cole ◽  
Amir M. Dabiran ◽  
Heiko O. Jacobs
Keyword(s):  
Reverse Bias ◽  
Forward Bias ◽  
Zno Nanowires ◽  
Hole Injection ◽  
Zno Nanowire ◽  
Defect States ◽  
Light Emitting ◽  
Current Voltage ◽  
Distinct Color ◽  
Two Peaks

AbstractThis article reports forward and reverse biased emission in vertical ZnO nanowire/p-GaN heterojunction light emitting diodes (LEDs) grown out of solution on Mg-doped p-GaN films. The electroluminescence spectra under forward and reverse bias are distinctly different. Forward bias showed two peaks centered around 390 nm and 585 nm, while reverse bias showed a single peak at 510 nm. Analysis of the current-voltage characteristics and electroluminescence spectra is presented to determine the transport mechanism and location of electron hole recombination. Reverse bias transport and luminescence are attributed to hot-hole injection from the ZnO nanowires into the GaN film through tunneling breakdown. Forward bias transport and luminescence are attributed to hole injection from the GaN into the ZnO and recombination at defect states inside the ZnO yielding distinct color variations between individual wires. Major resistive losses occurred in the GaN lateral thin film connecting to the vertical ZnO nanowires.

scholarly journals Optimization of p-type contacts to InGaN-based laser diodes and light emitting diodes grown by plasma assisted molecular beam epitaxy

2020 ◽  
Vol 50 (2) ◽  
Author(s):  
Krzesimir Nowakowski-Szkudlarek ◽  
Grzegorz Muziol ◽  
Mikolaj Żak ◽  
Mateusz Hajdel ◽  
Marcin Siekacz ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Contact Layer ◽  
Light Emitting ◽  
Mg Doping ◽  
Current Voltage ◽  
Type Contact ◽  
Current Voltage Characteristics ◽  
P Type ◽  
Diode Current

We investigated the influence of the In0.17Ga0.83N:Mg contact layer grown by plasma assisted molecular beam epitaxy on the resistivity of p-type Ni/Au contacts. We demonstrate that the Schottky barrier width for p-type contact is less than 5 nm. We compare circular transmission line measurements with a p-n diode current-voltage characteristics and show that discrepancies between these two methods can occur if surface quality is deteriorated. It is found that the most efficient contacts to p-type material consist of In0.17Ga0.83N:Mg contact layer with Mg doping level as high as 2 × 1020 cm–3.

Organic Light-Emitting Diodes Based on a Solution-Processable Benzimidazole-Functionalised Cationic Iridium Complex

2016 ◽  
Vol 69 (8) ◽  
pp. 890
Author(s):  
Xiujuan Zhi ◽  
Bin Du ◽  
Sichun Yuan
Keyword(s):  
Quantum Efficiency ◽  
Indium Tin Oxide ◽  
Power Efficiency ◽  
Light Emitting Diodes ◽  
Luminous Efficiency ◽  
Organic Light Emitting Diodes ◽  
Iridium Complex ◽  
High Brightness ◽  
Light Emitting ◽  
A Current

A cationic iridium(iii) complex with formula [Ir(ppy)2(pybmz)]+(PF6)– (ppy = 2-phenylpyridine; pybmz = 2-(pyridin-2-yl)-N-hexylbenzimidazole) was synthesised. The photoluminescence spectrum of the complex showed an orange–red emission peak at 590 nm with a quantum efficiency of 18 % and a luminescence lifetime of 1.2 µs in solid state. The complex was used as a phosphorescent dopant in light-emitting diodes with the configuration ITO/PEDOT : PSS(50 nm)/PVK (70) : PBD (30) : complex (x wt-%, x = 5, 20, 50, 100)(75nm)/TPBI(50nm)/Ba(4 nm)/Al(150 nm) [ITO = indium tin oxide; PEDOT = poly(ethylenedioxythiophene); PSS = poly(styrene sulfonic acid); PVK = polyvinylcarbazole; PBD = 5-(4-tert-butylphenyl)-2-(bi-phenyl-4-yl)-1,3,4-oxadiazole; TPBI = 1,3,5-tris-(2-N-phenylbenzimidazolyl) benzene]. The best device performances were obtained for the non-doped (100 wt-%) material, with an external quantum efficiency of 5.6 %, a luminous efficiency of 9.3 cd A–1, and a power efficiency of 3 lm W–1. High brightness of 8700 cd m–2 and luminous efficiency of 8 cd A–1 were realised at a current density of 110 mA cm–2.

scholarly journals Improvement of Light Extraction in Deep Ultraviolet GaN Light Emitting Diodes with Mesh P-Contacts

2020 ◽  
Vol 10 (17) ◽  
pp. 5783
Author(s):  
Shiou-Yi Kuo ◽  
Chia-Jui Chang ◽  
Zhen-Ting Huang ◽  
Tien-Chang Lu
Keyword(s):  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Ultra Violet ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Light Emitting ◽  
Duv Led ◽  
Lower Light ◽  
Deep Ultraviolet ◽  
P Type

One of the main reasons that the emission efficiency of GaN-based light-emitting diodes (LEDs) decreases significantly as the emission wavelength shorter than 300 nm is the low light extraction efficiency (LEE). Especially in deep ultra-violet (DUV) LEDs, light propagating outside the escape cone and being reflected back to the semiconductor or substrate layer is absorbed not only by active layers but also by p-type layers with narrower bandgaps and electrodes that are neither transparent nor reflective of the DUV wavelength. In this report, we propose a DUV LED structure with mesh p-GaN/indium-tin-oxide (ITO) contacts and a Ti/Al/Ni/Au layer as a reflective layer to improve LEE. The mesh p-GaN/ITO DUV LED showed an output power of 12% higher than that from the conventional DUV LED due to the lower light absorption at 280 nm.

scholarly journals A Flexible Blue Light-Emitting Diode Based on ZnO Nanowire/Polyaniline Heterojunctions

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Y. Y. Liu ◽  
X. Y. Wang ◽  
Y. Cao ◽  
X. D. Chen ◽  
S. F. Xie ◽  
...  
Keyword(s):  
Blue Light ◽  
Indium Tin Oxide ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Blue Light Emission ◽  
Light Emitting ◽  
Novel Device ◽  
Vertically Aligned ◽  
Doped Polyaniline ◽  
P Type

An organic/inorganic light-emitting diode (LED) consisting of n-type vertically aligned ZnO nanowires (NWs) and p-type proton acid doped polyaniline (PANi) is reported. The device was fabricated on flexible indium-tin-oxide (ITO) coated polyethylene terephthalate (PET) substrate. A broad blue light emission band ranging from 390 nm to 450 nm was observed in the electroluminescence (EL) spectra of the device, which was related to the interface recombination of electrons in the conduction band of ZnO NWs and holes in the polaron level of PANi. The turn-on voltage of the device is~3.5 V, lower than most of ZnO NWs based LED devices. In combination with the easy fabrication, flexibility, low power consumption, and mechanical robustness, this novel device is very promising in the application of blue LEDs.

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