Temperature-Dependent Charge Carrier Transfer in Colloidal Quantum Dot/Graphene Infrared Photodetectors

2020 ◽  
Author(s):  
Matthias Grotevent ◽  
Claudio U. Hail ◽  
Sergii Yakunin ◽  
Dominik Bachmann ◽  
Gökhan Kara ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Charge Carrier ◽  
Room Temperature ◽  
Red Light ◽  
Surface States ◽  
Surface Oxidation ◽  
Large Temperature ◽  
Temperature Dependent ◽  
Carrier Transfer ◽  
Specific Detectivity

Colloidal PbS quantum dot (QD)/graphene hybrid photodetectors are emerging QD technologies for affordable infra-red light detectors. By interfacing the QDs with graphene, the photosignal of these detectors is amplified, leading to high responsivity values. While these detectors have been mainly operated at room temperature, low-temperature operation is required for extending their spectral sensitivity beyond a wavelength of 3 μm. Here, we unveil the temperature-dependent response of PbS QD/graphene photodetectors by performing steady-state and time-dependent measurements over a large temperature range of 80–300 K. We find that the temperature dependence of photo-induced charge carrier transfer from the QD layer to graphene is (i) not impeded by freeze-out of the (Schottky-like) potential barrier at low temperatures, (ii) tremendously sensitive to QD surface states (surface oxidation), and (iii) minimally affected by the ligand exposure time and QD layer thickness. Moreover, the specific detectivity of our detectors increases with cooling, with a maximum measured specific detectivity of at least 10<sup>10</sup> Jones at a wavelength of 1280 nm and temperature of 80 K, which is an order of magnitude larger compared to the corresponding room temperature value. The temperature- and gate-voltage-dependent characterization presented here constitute an important step in expanding our knowledge of charge transfer at interfaces of low dimensional materials and towards the realization of next-generation optoelectronic devices.<br>

Temperature-Dependent Charge Carrier Transfer in Colloidal Quantum Dot/Graphene Infrared Photodetectors

2020 ◽  
Author(s):  
Matthias Grotevent ◽  
Claudio U. Hail ◽  
Sergii Yakunin ◽  
Dominik Bachmann ◽  
Gökhan Kara ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Charge Carrier ◽  
Room Temperature ◽  
Red Light ◽  
Surface States ◽  
Surface Oxidation ◽  
Large Temperature ◽  
Temperature Dependent ◽  
Carrier Transfer ◽  
Specific Detectivity

Colloidal PbS quantum dot (QD)/graphene hybrid photodetectors are emerging QD technologies for affordable infra-red light detectors. By interfacing the QDs with graphene, the photosignal of these detectors is amplified, leading to high responsivity values. While these detectors have been mainly operated at room temperature, low-temperature operation is required for extending their spectral sensitivity beyond a wavelength of 3 μm. Here, we unveil the temperature-dependent response of PbS QD/graphene photodetectors by performing steady-state and time-dependent measurements over a large temperature range of 80–300 K. We find that the temperature dependence of photo-induced charge carrier transfer from the QD layer to graphene is (i) not impeded by freeze-out of the (Schottky-like) potential barrier at low temperatures, (ii) tremendously sensitive to QD surface states (surface oxidation), and (iii) minimally affected by the ligand exposure time and QD layer thickness. Moreover, the specific detectivity of our detectors increases with cooling, with a maximum measured specific detectivity of at least 10<sup>10</sup> Jones at a wavelength of 1280 nm and temperature of 80 K, which is an order of magnitude larger compared to the corresponding room temperature value. The temperature- and gate-voltage-dependent characterization presented here constitute an important step in expanding our knowledge of charge transfer at interfaces of low dimensional materials and towards the realization of next-generation optoelectronic devices.<br>

Temperature-Dependent Charge Carrier Transfer in Colloidal Quantum Dot/Graphene Infrared Photodetectors

2020 ◽  
Author(s):  
Matthias J. Grotevent ◽  
Claudio U. Hail ◽  
Sergii Yakunin ◽  
Dominik Bachmann ◽  
Gökhan Kara ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Charge Carrier ◽  
Infrared Photodetectors ◽  
Temperature Dependent ◽  
Carrier Transfer ◽  
Colloidal Quantum Dot

scholarly journals Deciphering the role of quantum dot size in the ultrafast charge carrier dynamics at the perovskite–quantum dot interface

2020 ◽  
Vol 8 (42) ◽  
pp. 14834-14844
Author(s):  
Piotr Piatkowski ◽  
Sofia Masi ◽  
Pavel Galar ◽  
Mario Gutiérrez ◽  
Thi Tuyen Ngo ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Charge Carrier ◽  
Rate Constants ◽  
Transient Absorption ◽  
Carrier Dynamics ◽  
Carrier Transfer ◽  
Charge Carrier Dynamics ◽  
Conduction Bands

Charge-carrier transfer (CT) from the perovskite host to PbS QDs were studied using fs-transient absorption and THz techniques. The CT rate constants increase with the size of QDs due to a change in the position of valence and conduction bands in PbS QDs.

Persistent Photoconductivity in Bulk Strontium Titanate

2014 ◽  
Vol 1675 ◽  
pp. 87-91
Author(s):  
Matthew D. McCluskey ◽  
Caleb D. Corolewski ◽  
Violet M. Poole ◽  
Marianne C. Tarun
Keyword(s):  
Strontium Titanate ◽  
Room Temperature ◽  
Large Temperature ◽  
Bulk Single Crystal ◽  
Persistent Photoconductivity ◽  
Temperature Dependent ◽  
Free Electron Density ◽  
Novel Applications ◽  
Enhanced Conductivity ◽  
Intense Debate

ABSTRACTStrontium titanate (SrTiO3) has novel properties, including a large temperature-dependent dielectric constant, and can be doped to make it metallic or even superconducting. The origin of conductivity observed at the SrTiO3/LaAlO3 interface is a topic of intense debate. In the present work, bulk single crystal SrTiO3 samples were heated at 1200°C, with the goal of producing cation vacancies. These thermally treated samples exhibited persistent photoconductivity (PPC) at room temperature. Upon exposure to sub-band-gap light (>2.9 eV), the free-electron density increases by over two orders of magnitude. This enhanced conductivity persists in the dark, at room temperature, for several days with essentially no decay. Light excites an electron from the vacancy to the conduction band, where it remains, due to a large recapture barrier. These observations highlight the importance of defects in determining the electrical properties of oxides and may point toward novel applications.

InN/GaN quantum dot superlattices: Charge-carrier states and surface electronic structure

2018 ◽  
Vol 32 (06) ◽  
pp. 1850060
Author(s):  
F. Kanouni ◽  
A. Brezini ◽  
M. Djenane ◽  
Q. Zou
Keyword(s):  
Quantum Dot ◽  
Charge Carrier ◽  
Surface States ◽  
Energy Bands ◽  
Surface Electronic Structure ◽  
Quantum Numbers ◽  
Effective Mass Schrödinger Equation ◽  
Calculation Results ◽  
Matching Procedure

We have theoretically investigated the electron energy spectra and surface states energy in the three dimensionally ordered quantum dot superlattices (QDSLs) made of InN and GaN semiconductors. The QDSL is assumed in this model to be a matrix of GaN containing cubic dots of InN of the same size and uniformly distributed. For the miniband’s structure calculation, the resolution of the effective mass Schrödinger equation is done by decoupling it in the three directions within the framework of Kronig–Penney model. We found that the electrons minibands in infinite ODSLs are clearly different from those in the conventional quantum-well superlattices. The electrons localization and charge-carrier states are very dependent on the quasicrystallographic directions, the size and the shape of the dots which play a role of the artificial atoms in such QD supracrystal. The energy spectrum of the electron states localized at the surface of InN/GaN QDSL is represented by Kronig–Penney like-model, calculated via direct matching procedure. The calculation results show that the substrate breaks symmetrical shape of QDSL on which some localized electronic surface states can be produced in minigap regions. Furthermore, we have noticed that the surface states degeneracy is achieved in like very thin bands located in the minigaps, identified by different quantum numbers n[Formula: see text], n[Formula: see text], n[Formula: see text]. Moreover, the surface energy bands split due to the reduction of the symmetry of the QDSL in z-direction.

Heavy Mediator at Quantum Dot/Graphene Heterojunction for Efficient Charge Carrier Transfer: Alternative Approach for High-Performance Optoelectronic Devices

2019 ◽  
Vol 11 (29) ◽  
pp. 26518-26527 ◽  
Author(s):  
Rapti Ghosh ◽  
Kanchan Yadav ◽  
Monika Kataria ◽  
Hung-I Lin ◽  
Christy Roshini Paul Inbaraj ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Charge Carrier ◽  
High Performance ◽  
Optoelectronic Devices ◽  
Carrier Transfer ◽  
Alternative Approach ◽  
Efficient Charge

A Comparative Study of an Inp Quantum Dot Laser and A GAxIN(1-X)P Quantum Well Laser

2002 ◽  
Vol 722 ◽  
Author(s):  
Y. M. Manz ◽  
O. G. Schmidt
Keyword(s):  
Quantum Dot ◽  
Quantum Well ◽  
Comparative Study ◽  
Current Density ◽  
Red Light ◽  
Emission Spectra ◽  
Threshold Current ◽  
Threshold Current Density ◽  
Temperature Dependent ◽  
Light Emitting

AbstractA comparative study between a red-light emitting quantum dot (QD) and quantum well (QW) laser, grown in the same solid-source molcular beam epitaxy (SSMBE) machine under the same conditions, is presented. The QD laser consists of a threefold stack of 3.5 ML InP dots and the QW laser of a 4.5 nm thick compressively strained Ga30In70P layer, both embedded in a Ga52In48P waveguide. The threshold current density of the QD laser is jthr = 1.8 kA/cm2 at 300 K and more than twice as large for the QW laser. Moreover, temperature dependent analysis of spontaneous emission spectra reveals that the threshold current density of the QD device is less temperature dependent than that of the QW laser, although the linewidth of the QD samples is larger.

scholarly journals Temperature-mediated tribological characteristics of 40CrNiMoA steel and Inconel 718 alloy during sliding against Si3N4 counterparts

Friction ◽  
2020 ◽  
Author(s):  
Liuyang Bai ◽  
Shanhong Wan ◽  
Gewen Yi ◽  
Yu Shan ◽  
Sang The Pham ◽  
...  
Keyword(s):  
Inconel 718 ◽  
Friction And Wear ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Effect Of Temperature ◽  
Large Temperature ◽  
Structural Adaptation ◽  
Temperature Dependent ◽  
Inconel 718 Alloy ◽  
Ambient Temperatures

AbstractA comparative evaluation of the friction and wear behaviors of 40CrNiMoA steel and Inconel 718 alloy sliding against Si3N4 counterparts was conducted over a large temperature range from room temperature (RT) to 800 °C. The temperature-dependent tribological properties associated with the resulting chemical mitigation and structural adaptation of the solid sliding surface were clarified by surface/interface characterizations. The results revealed desirable performance in reducing friction and wear at elevated temperatures, which was associated with the resulting oxide composite film’s adaptive lubricating capability, whereas severe abrasive wear occurred at room/ambient temperatures. The oxidative-abrasive differentials for the two alloys were further discussed by considering the combined effect of temperature and stressed-shearing conditions.

scholarly journals Раскрытие энергетической щели в области точки Дирака при осаждении кобальта на поверхность (0001) топологического изолятора BiSbTeSe-=SUB=-2-=/SUB=-

2020 ◽  
Vol 54 (9) ◽  
pp. 859
Author(s):  
А.К. Кавеев ◽  
А.Г Банщиков ◽  
А.Н Терпицкий ◽  
В.А Голяшов ◽  
О.Е Терещенко ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Room Temperature ◽  
Molecular Beam ◽  
Dirac Point ◽  
Surface States ◽  
Energy Band Gap ◽  
Temperature Dependent ◽  
Molecular Beam Epitaxy Method ◽  
Topological Surface ◽  
First Time

It was shown for the first time that Co subnanometer coaverage, being deposited by molecular beam epitaxy method onto the (0001) surface of the BiSbTeSe2 topological insulator at 330 °C, opens an energy band gap in the spectrum of topological surface states in the region of the Dirac point, with a shift in the position of the Dirac point caused by preliminary deposition of the adsorbate at room temperature. The gap band width is 21 +/- 6 meV. Temperature-dependent measurements in the 15-150 K range did not show any width changes.

Quantitative measurements of charge carrier hopping transport properties in depleted-heterojunction PbS colloidal quantum dot solar cells from temperature dependent current–voltage characteristics

RSC Advances ◽  
2016 ◽  
Vol 6 (95) ◽  
pp. 93180-93194 ◽  
Author(s):  
Andreas Mandelis ◽  
Lilei Hu ◽  
Jing Wang
Keyword(s):  
Solar Cells ◽  
Quantum Dot ◽  
Charge Carrier ◽  
Temperature Dependent ◽  
Hopping Transport ◽  
Quantitative Measurements ◽  
Quantum Dot Solar Cells ◽  
Current Voltage ◽  
Colloidal Quantum Dot ◽  
Current Voltage Characteristics

Non-conventional (anomalous) current–voltage characteristics are reported with increasing frequency for colloidal quantum dot-based (CQD) solar cells.

Sign in / Sign up

Export Citation Format

Share Document