HYBRID NANOMATERIALS FOR MULTI-SPECTRAL INFRARED PHOTODETECTION

2007 ◽  
Vol 17 (01) ◽  
pp. 165-172 ◽  
Author(s):  
ADRIENNE D. STIFF-ROBERTS
Keyword(s):  
Dark Current ◽  
Room Temperature ◽  
Spectral Response ◽  
Substrate Material ◽  
Hybrid Nanomaterials ◽  
Thermally Activated ◽  
Dopant Incorporation ◽  
Quantum Dot Infrared Photodetectors ◽  
Current Voltage ◽  
Fourier Transform Ir

Quantum dot infrared photodetectors (QDIPs) using quantum dots (QDs) grown by strained-layer epitaxy have demonstrated low dark current, multi-spectral response, high operating temperature, and infrared (IR) imaging. However, achieving near room-temperature, multi-spectral operation is a challenge due to randomness in QD properties. The ability to control dopant incorporation is important since charge carrier occupation influences dark current and IR spectral response. In this work, dopant incorporation is investigated in two classes of QDs; epitaxial InAs/GaAs QDs and CdSe colloidal QDs (CQDs) embedded in MEH-PPV conducting polymers. The long-term goal of this work is to combine these hybrid nanomaterials in a single device heterostructure to enable multi-spectral IR photodetection. Two important results towards this goal are discussed. First, by temperature-dependent dark current-voltage and polarization-dependent Fourier transform IR spectroscopy measurements in InAs/GaAs QDIPs featuring different doping schemes, we have provided experimental evidence for the important contribution of thermally-activated, defect-assisted, sequential resonant tunneling. Second, the enhanced quantum confinement and electron localization in the conduction band of CdSe / MEH-PPV nanocomposites enable intraband transitions in the mid-IR at room temperature. Further, by controlling the semiconductor substrate material, doping type, and doping level on which these nanocomposites are deposited, the intraband IR response can be tuned.

Spectral response, dark current, and noise analyses in resonant tunneling quantum dot infrared photodetectors

2016 ◽  
Vol 55 (30) ◽  
pp. 8494 ◽  
Author(s):  
Hamed Dehdashti Jahromi ◽  
Ali Mahmoodi ◽  
Mohammad Hossein Sheikhi ◽  
Abbas Zarifkar
Keyword(s):  
Quantum Dot ◽  
Dark Current ◽  
Resonant Tunneling ◽  
Spectral Response ◽  
Infrared Photodetectors ◽  
Quantum Dot Infrared Photodetectors

Morphology and I-V Characteristics of Electrochemically Deposited Zinc Oxide on Silicon

2021 ◽  
Vol 20 (3) ◽  
pp. 32-36
Author(s):  
Ahmad Bukhairi Md Rashid ◽  
Mastura Shafinaz Zainal Abidin ◽  
Shaharin Fadzli Abd Rahman ◽  
Amirjan Nawabjan
Keyword(s):  
Zinc Oxide ◽  
Electrochemical Deposition ◽  
Dark Current ◽  
Room Temperature ◽  
Volume Ratio ◽  
Deposition Process ◽  
X Ray ◽  
Current Voltage ◽  
Electrochemically Deposited ◽  
A Current

This paper reported on the electrochemical deposition of zinc oxide (ZnO) on p-silicon (p-Si) (100) substrate in the mixture of 0.1 M of zinc chloride (ZnCl2) and potassium chloride (KCl) electrolyte at a volume ratio of 1:1, 3:1 and 5:1 namely Sample A, B and C. The deposition process was done in room temperature with a current density of 10 mA/cm2 for 30 minutes. Prior to the experiment, all samples were treated by RCA cleaning steps. All samples were characterized using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The results show that all samples have the same morphology of a flake-like structure with different Zn:O ratio that were 2.81, 2.35 and 2.49 for samples A, B and C. The current-voltage (I-V) characteristic graph was obtained by dark current measurement using Keithley SMU 2400 and the threshold voltage (Vth) values were determined at 2.21 V, 0.85 V and 1.22 V for sample A, B and C respectively which correspond with the Zn:O ratio where the highest value of Zn:O ratio can be found in sample A and the lowest in sample B. Based on these results, it shows that electrochemical deposition technique is capable of being used to deposit the flake-like structure ZnO on semiconductor material to form the p-n junction which behaves like a diode. The value of Vth seems to be depended on the ratio between Zn and O. Higher ratio of Zn and O will cause the higher value of intrinsic carrier concentration and built in potential which will increase the Vth value.

Efficient Cu(In, Ga)Se2 Based Solar Cells Prepared by Electrodeposition

2003 ◽  
Vol 763 ◽  
Author(s):  
D. Guimard ◽  
N. Bodereau ◽  
J. Kurdi ◽  
J.F. Guillemoles ◽  
D. Lincot ◽  
...  
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Open Circuit Voltage ◽  
Spectral Response ◽  
Deposition Process ◽  
Open Circuit ◽  
Response Analysis ◽  
Cell Parameters ◽  
Current Voltage ◽  
Capacitance Voltage

AbstractCuInSe2 and Cu(In, Ga)Se2 precursor layers have been prepared by electrodeposition, with morphologies suitable for device completion. These precursor films were transformed into photovoltaic quality films after thermal annealing without any post-additional vacuum deposition process. Depending on the preparation parameters annealed films with different band gaps between 1eV and 1.5 eV have been prepared. The dependence of resulting solar cell parameters has been investigated. The best efficiency achieved is about 10,2 % for a band gap of 1.45 eV. This device presents an open circuit voltage value of 740 mV, in agreement with the higher band gap value. Device characterisations (current-voltage, capacitance-voltage and spectral response analysis) have been performed. Admittance spectroscopy at room temperature indicates the presence of two acceptor traps at 0.3 and 0.43 eV from the valance band with density of the order of 2. 1017 cm-3 eV-1.

ON THE ANOMALOUS STEADY-STATE DARK CONDUCTIVITY INa-SeFILMS

2009 ◽  
Vol 23 (26) ◽  
pp. 5171-5177 ◽  
Author(s):  
N. QAMHIEH ◽  
I. M. OBAIDAT ◽  
F. HAMED
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Dark Conductivity ◽  
Amorphous Selenium ◽  
Conductivity Measurements ◽  
Thermally Activated ◽  
Current Voltage ◽  
Chalcogenide Semiconductors ◽  
Dark Currents

Thin films of amorphous selenium ( a-Se ) have been prepared by thermal evaporation. DC conductivity measurements were carried out on these films in the temperature range between 60 and -50° C . Above room temperature, the dark conductivity is thermally activated as usually observed in chalcogenide semiconductors. At low temperatures, the unexpected increase in the dark currents could be attributed to the phase change in the a-Se film. The current–voltage, I–V, curves showed a phase transition temperature of about 10°C.

Effects of Grain Boundaries in Amorphous/Multicrystalline Silicon Heterojunction Photovoltaic Cells

2004 ◽  
Vol 836 ◽  
Author(s):  
M. Farrokh Baroughi ◽  
S. Sivoththaman
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Dark Current ◽  
Spectral Response ◽  
Simulation Software ◽  
Multicrystalline Silicon ◽  
Consistent Difference ◽  
Photovoltaic Properties ◽  
Current Voltage ◽  
Current Voltage Characteristics

ABSTRACTSpectral response and dark current-voltage characteristics of heterojunctions are used to investigate grain boundary degradation in photovoltaic properties of a-Si/mc-Si heterojunction solar cells. Measured spectral response inside the grain and on the grain boundary shows small but consistent QE degradation due to minority carrier recombination at the grain boundaries. No consistent difference is observed in dark current-voltage characteristics because of large diode area and periphery leakage current in the employed heterojunction diodes. Comparing measurement results and results from device modeling using the simulation software Medici, a recombination velocity of 4900 cm/sec is found at the grain boundaries of employed multicrystalline silicon wafer. The modeling and experimental results can also be used to define an effective grain area that serves as a measure of grain boundary recombination and the influence of grain size.

Analysis of the Bias Dependent Spectral Response of a-SiC:H p-i-n Photodiode

2002 ◽  
Vol 715 ◽  
Author(s):  
P. Louro ◽  
A. Fantoni ◽  
Yu. Vygranenko ◽  
M. Fernandes ◽  
M. Vieira
Keyword(s):  
Bias Voltage ◽  
Voltage Dependence ◽  
Spectral Response ◽  
Surface Recombination ◽  
Electrical Field ◽  
Field Reversal ◽  
Current Voltage ◽  
Voltage Dependent ◽  
And Inversion ◽  
Device Operation

AbstractThe bias voltage dependent spectral response (with and without steady state bias light) and the current voltage dependence has been simulated and compared to experimentally obtained values. Results show that in the heterostructures the bias voltage influences differently the field and the diffusion part of the photocurrent. The interchange between primary and secondary photocurrent (i. e. between generator and load device operation) is explained by the interaction of the field and the diffusion components of the photocurrent. A field reversal that depends on the light bias conditions (wavelength and intensity) explains the photocurrent reversal. The field reversal leads to the collapse of the diode regime (primary photocurrent) launches surface recombination at the p-i and i-n interfaces which is responsible for a double-injection regime (secondary photocurrent). Considerations about conduction band offsets, electrical field profiles and inversion layers will be taken into account to explain the optical and voltage bias dependence of the spectral response.

Laser Engineering of Barrier Structures Based on Solid Solution ZnCdHgTe.

2002 ◽  
Vol 719 ◽  
Author(s):  
Galina Khlyap
Keyword(s):  
Room Temperature ◽  
Film Surface ◽  
Charge Carriers ◽  
Barrier Structure ◽  
Free Charge ◽  
Current Voltage ◽  
Capacitance Voltage ◽  
Laser Engineering ◽  
Charged Defects ◽  
Epilayer Surface

AbstractRoom-temperature electric investigations carried out in CO2-laser irradiated ZnCdHgTe epifilms revealed current-voltage and capacitance-voltage dependencies typical for the metal-semiconductor barrier structure. The epilayer surface studies had demonstrated that the cell-like relief has replaced the initial tessellated structure observed on the as-grown samples. The detailed numerical analysis of the experimental measurements and morphological investigations of the film surface showed that the boundaries of the cells formed under the laser irradiation are appeared as the regions of accumulation of derived charged defects of different type of conductivity supplying free charge carriers under the applied electric field.

Mass spectrometric study of allyl radical, allyl bromide and 1,5-hexadiene interactions with oxides; Cobalt suboxide Co3O4

1979 ◽  
Vol 44 (7) ◽  
pp. 2009-2014 ◽  
Author(s):  
Jana Nováková ◽  
Zdeněk Dolejšek
Keyword(s):  
Room Temperature ◽  
Allyl Bromide ◽  
Catalytic Properties ◽  
Mass Spectrometric Study ◽  
Spectrometric Study ◽  
Flow Conditions ◽  
Allyl Radical ◽  
Knudsen Flow ◽  
Thermally Activated ◽  
Radical Interaction

Products of (a) allyl radical interaction with unheated Co3O4, (b) thermally activated 1,5-hexadiene or thermally activated allyl bromide with unheated Co3O4, (c) moderately heated Co3O4 with unheated 1,5-hexadiene or allyl bromide were studied under Knudsen flow conditions. Cobalt suboxide Co3O4, a typical catalyst of deep oxidations yielded acrolein in reaction with allyl radicals as early as at the room temperature of the catalyst. A similar acrolein formation was also observed in the allyl radical interaction with other oxides exhibiting different catalytic properties. It appears that acrolein is in general the primary product of the allyl radical interaction with the oxides. The results are discussed and compared with previous data obtained with MoO3.

scholarly journals Blackbody-sensitive room-temperature infrared photodetectors based on low-dimensional tellurium grown by chemical vapor deposition

2021 ◽  
Vol 7 (16) ◽  
pp. eabf7358
Author(s):  
Meng Peng ◽  
Runzhang Xie ◽  
Zhen Wang ◽  
Peng Wang ◽  
Fang Wang ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Spectral Response ◽  
Chemical Vapor ◽  
Hole Mobility ◽  
Infrared Detection ◽  
Infrared Photodetectors ◽  
Bandgap Semiconductors ◽  
Low Dimensional

Blackbody-sensitive room-temperature infrared detection is a notable development direction for future low-dimensional infrared photodetectors. However, because of the limitations of responsivity and spectral response range for low-dimensional narrow bandgap semiconductors, few low-dimensional infrared photodetectors exhibit blackbody sensitivity. Here, highly crystalline tellurium (Te) nanowires and two-dimensional nanosheets were synthesized by using chemical vapor deposition. The low-dimensional Te shows high hole mobility and broadband detection. The blackbody-sensitive infrared detection of Te devices was demonstrated. A high responsivity of 6650 A W−1 (at 1550-nm laser) and the blackbody responsivity of 5.19 A W−1 were achieved. High-resolution imaging based on Te photodetectors was successfully obtained. All the results suggest that the chemical vapor deposition–grown low-dimensional Te is one of the competitive candidates for sensitive focal-plane-array infrared photodetectors at room temperature.

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