Pyroelectric and Piezoelectric Properties of Gan-Based Materials

1998 ◽  
Vol 537 ◽  
Author(s):  
M. S. Shur ◽  
A. D. Bykhovski ◽  
R. Gaska
Keyword(s):  
High Temperature ◽  
Piezoelectric Properties ◽  
Pyroelectric Coefficient ◽  
Heating Regime ◽  
Light Emitting ◽  
Polarization Effects ◽  
Light Emitting Devices ◽  
Uniform Sample ◽  
Piezoelectric Effects ◽  
Pyroelectric Detectors

AbstractWe review pyroelectric and piezoelectric properties of GaN-based materials. Pyroelectric effects in GaN have been studied in two different regimes: (i) uniform sample heating regime and (ii) under applied temperature gradient along the sample. The modeling results show that the pyroelectric coefficient, Pv, in GaN (for c-axis along the contacts) can reach 7x105 V/m-K (compared to Pv = 5x105 V/m-K for the best-known high temperature pyroelectric/piezoelectric material LiTaO3). This points to a high potential of GaN-based sensors for high temperature pyroelectronics. Piezoelectric effects strongly affect the performance of electronic and light-emitting devices based on III-N materials. Piezoelectrically induced charge in heterostructures can be as large as 3 to 4x1013 cm-2. Hence, strong lattice polarization effects provide unique possibilities for utilizing GaN-based materials in high temperature piezoelectronics and for their applications in pyroelectric detectors.

scholarly journals Pyroelectric and Piezoelectric Properties of GaN-Based Materials

1999 ◽  
Vol 4 (S1) ◽  
pp. 57-68 ◽  
Author(s):  
R. Gaska ◽  
M. S. Shur ◽  
A. D. Bykhovski
Keyword(s):  
High Temperature ◽  
Piezoelectric Properties ◽  
Pyroelectric Coefficient ◽  
Heating Regime ◽  
Light Emitting ◽  
Polarization Effects ◽  
Light Emitting Devices ◽  
Uniform Sample ◽  
Piezoelectric Effects ◽  
Pyroelectric Detectors

We review pyroelectric and piezoelectric properties of GaN-based materials. Pyroelectric effects in GaN have been studied in two different regimes: (i) uniform sample heating regime and (ii) under applied temperature gradient along the sample. The modeling results show that the pyroelectric coefficient, Pv, in GaN (for c-axis along the contacts) can reach 7×105 V/m-K (compared to Pv = 5×105 V/m-K for the best-known high temperature pyroelectric/piezoelectric material LiTaO3). This points to a high potential of GaN-based sensors for high temperature pyroelectronics. Piezoelectric effects strongly affect the performance of electronic and light-emitting devices based on III-N materials. Piezoelectrically induced charge in heterostructures can be as large as 3 to 4×1013 cm−2. Hence, strong lattice polarization effects provide unique possibilities for utilizing GaN-based materials in high temperature piezoelectronics and for their applications in pyroelectric detectors.

Photoluminescence Properties of Ca3Si2O7: Pr3+ Orange-Red Phosphors Prepared by High-Temperature Solid-State Method

2018 ◽  
Vol 73 (6) ◽  
pp. 555-558 ◽  
Author(s):  
Zhi-Qing Peng ◽  
Rong Chen ◽  
Wen-Lin Feng
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Solid State ◽  
Solid State Method ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Red Phosphors ◽  
Typical Sample ◽  
State Method ◽  
Xrd Patterns

AbstractNovel luminescent materials Ca3-xSi2O7: xPr3+ were successfully prepared by the high-temperature solid-state method. The crystal structure, morphology, and optical spectrum were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectroscopy, respectively. The XRD patterns of the samples indicate that the crystal structure is monoclinic symmetry. The SEM shows that the selected sample has good crystallinity although its appearance is irregular and scalelike. The peak of the excitation spectrum of the sample is located at around 449 nm, corresponding to 3H4→3P2 transition of Pr3+. The peak of the emission spectrum of the sample is situated at around 612 nm which is attributed to 3P0→3H6 transition of Pr3+, and the colour is orange-red. The optimum concentration for Pr3+ replaced Ca2+ sites in Ca3Si2O7: Pr3+ is 0.75 mol%. The lifetime (8.48 μs) of a typical sample (Ca2.9925Pr0.0075)Si2O7 is obtained. It reveals that orange-red phosphors Ca3-xSi2O7: xPr3+ possess remarkable optical properties and can be used in white light emitting devices.

scholarly journals Bright Alloy CdZnSe/ZnSe QDs with Nonquenching Photoluminescence at High Temperature and Their Application to Light-Emitting Diodes

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Tingting Zhang ◽  
Xugu Zhang ◽  
Peizhi Yang ◽  
Jinke Bai ◽  
Chun Chang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Temperature ◽  
Quantum Yields ◽  
Excellent Performance ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Maximum Current Density ◽  
Luminescence Efficiency ◽  
Maximum Current ◽  
Pl Quenching

Stable luminance properties are essential for light-emitting devices with excellent performance. Thermal photoluminescence (PL) quenching of quantum dots (QDs) under a high temperature resulting from a surface hole or electron traps will lead to unstable and dim brightness. After treating CdZnSe/ZnSe QDs with TBP, which is a well-known passivation reagent of the anions, the excess Se sites on the surface of the QDs were removed and their PL quantum yields (QYs) was improved remarkable. Furthermore, after TBP treatment, the CdZnSe/ZnSe QDs exhibit no quenching phenomena even at a high temperature of 310°C. The electroluminescent light-mitting diodes based on the QDs with TBP treatment also demonstrated satisfied performance with a maximum current density of 1679.6 mA/cm2, a peak luminance of 89500 cd/m2, and the maximum values of EQE and luminescence efficiency are 15% and 14.9 cd/A, respectively. The performance of the fabricated devices can be further improved providing much more in-depth studies on the CdZnSe/ZnSe QDs.

Epitaxial Growth of Spinel Ferrite Oxide (Al,Ru,Fe)3O4 on a GaAs(001) Substrate Using a MgO Buffer Layer

2007 ◽  
Vol 1034 ◽  
Author(s):  
Teruo Kanki ◽  
Toshio Kawahara ◽  
Naoki Asakawa ◽  
Yasushi Hotta ◽  
Yoshikazu Terai ◽  
...  
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Light Emission ◽  
Spinel Ferrite ◽  
Buffer Layers ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Direct Light ◽  
Magnetic Ions ◽  
Lattice Matched

AbstractSpinel ferrite oxides doping non-magnetic ions show the photo-induced magnetization (PIM) effect at high temperature [1-3]. Such a magnetization enhancement by light irradiation is a unique property in this material. In order effectively to use the PIM effect and precisely to control the magnetism, direct light-emission from light-emitting element substrates would be a useful technique. In this study, spinel ferrite Al0.2Ru0.8Fe2O4 (ARFO) thin films, with the high temperature PIM effect, were prepared on GaAs(001) substrates by a pulsed laser deposition technique to aim integration with light-emitting devices based on GaAs lattice-matched materials in the future. Results showed that (001)-oriented ARFO thin films were successfully grown by using MgO buffer layers. The magnetic properties were approximately the same as ARFO films using other substrates such as Al2O3(0001) or MgO(001).

scholarly journals High-Temperature Electroluminescence of InGaN/GaN Light-Emitting Devices with Multiple Quantum Barriers

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Ya-Fen Wu
Keyword(s):  
High Temperature ◽  
Quantum Well ◽  
External Quantum Efficiency ◽  
Multiple Quantum Well ◽  
Current Level ◽  
Multiple Quantum ◽  
Carrier Localization ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
High Temperature Operation

We investigate the high-temperature characteristics of InGaN/GaN multiple quantum well light-emitting devices with and without multiple quantum barriers (MQBs) in depth. The electroluminescence measurements were carried out over a temperature range from 200 to 380 K and an injection current level from 1 to 100 mA. Enhanced carrier confinement and stronger carrier localization in the active layer are achieved for the sample with MQBs. Furthermore, it is found that the external quantum efficiency of the sample possessing MQBs is higher than that of the sample with GaN barriers. The MQB structure improves the high-temperature operation of light-emitting devices.

Heterostructures based on nitrides of group III elements: technical processes, properties, and light-emitting devices

2001 ◽  
Vol 171 (8) ◽  
pp. 857 ◽  
Author(s):  
Igor L. Krestnikov ◽  
V.V. Lundin ◽  
A.V. Sakharov ◽  
D.A. Bedarev ◽  
E.E. Zavarin ◽  
...  
Keyword(s):  
Light Emitting ◽  
Group Iii ◽  
Light Emitting Devices

Probing local photophysical properties in perovskite based light-emitting devices

2019 ◽  
Author(s):  
Miguel Anaya ◽  
Kyle Frohna ◽  
Linsong Cui ◽  
Javad Shamsi ◽  
Sam Stranks
Keyword(s):  
Photophysical Properties ◽  
Light Emitting ◽  
Light Emitting Devices
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