The breakdown of the temperature dependence of the photoluminescence peak position in single asymmetric quantum wells

2001 ◽  
Vol 53 (6) ◽  
pp. 790-796 ◽  
Author(s):  
Fanyao Qu ◽  
N. O Dantas ◽  
P. C Morais
Keyword(s):  
Quantum Wells ◽  
Temperature Dependence ◽  
Peak Position ◽  
Asymmetric Quantum ◽  
Photoluminescence Peak

High-pressure investigation of InGan quantum wells.

1998 ◽  
Vol 512 ◽  
Author(s):  
Piotr Perlin ◽  
Valentin Iota ◽  
Bernie A. Weinstein ◽  
Henryk Teisseyre ◽  
Tadeusz Suski ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Energy Gap ◽  
Pressure Coefficient ◽  
Peak Position ◽  
Emission Peak ◽  
Pressure Coefficients ◽  
Classical Quantum ◽  
The One ◽  
Photoluminescence Peak ◽  
Ingan Quantum Wells

ABSTRACTWe have studied the pressure dependence of photoluminescence for various InGaN quantum wells of different Indium compositions. In contrast to classical quantum well systems such as GaAs/AlGaAs, the pressure coefficients of the photoluminescence peak position of wells of similar parameters can vary greatly, depending on conditions of growth. Generally, the pressure coefficient of the emission peak is much lower than the one predicted for a GaN-InN system. We show that this behavior can be related in most cases to the influence of the thick GaN layer compressibility on the strain in the InGaN quantum wells. However, in some cases (Nichia devices), the pressure coefficient of the emission peak seems to be unrelated to the shift of the energy gap of the material, suggesting the involvement of strongly localized electronic states

Ferromagnetism and Luminescence of Diluted Magnetic Semiconductors GaGdN and AlGdN

2008 ◽  
Vol 1111 ◽  
Author(s):  
Shuichi Emura ◽  
Masahiro Takahashi ◽  
Hiroyuki Tambo ◽  
Akira Suzuki ◽  
Tetsuya Nakamura ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Magnetic Circular Dichroism ◽  
Peak Position ◽  
Magnetic Characteristics ◽  
Sharp Line ◽  
X Ray ◽  
Diluted Magnetic ◽  
X Ray Absorption

AbstractThe magnetic characteristics of the dilute magnetic system GaGdN are investigated by mainly soft-X-ray magnetic circular dichroism (MCD) in energy range of 1160 – 1240 eV. The strong MCD signals up to 30 % at 15K are observed. The temperature dependence of its intensity is not on simple Curie-Weiss curve and depicts three-step curve. A step around 40 – 100K suggests a new magnetic phase. The luminescence spectrum of GaGdN at low temperature is divided into three parts consisting of two broad bands around 432 nm and 503 nm and a sharp peak at 652 nm. This sharp line is assigned to the intra-transition of f – f orbital owing to the weak temperature dependence of the intensity and peak position. AlGdN grown by molecular beam epitaxy produces luminescence at 318.5 nm. X-ray absorption fine structure is examined to survey the occupancy of the Gd ion in the grown specimens.

Third-Harmonic Generation in Special Parabolic Quantum Wells

2013 ◽  
Vol 760-762 ◽  
pp. 392-396
Author(s):  
You Bin Yu
Keyword(s):  
Quantum Well ◽  
Density Matrix ◽  
Quantum Wells ◽  
Harmonic Generation ◽  
Third Harmonic Generation ◽  
Third Harmonic ◽  
The Third ◽  
Compact Density ◽  
Asymmetric Quantum ◽  
Parabolic Quantum Wells

Third-harmonic generation in a special asymmetric quantum well is investigated. The third-harmonic generation coefficient is carried out by applying compact-density-matrix method. The numerical results are presented for a GaAs/AlGaAs asymmetric quantum well. The very large third-harmonic generation coefficient is obtained in this quantum well. Moreover, the third-harmonic generation coefficient dependents on the quantum well parameters are investigated, respectively.

scholarly journals Dynamics of Anomalous Temperature-Induced Emission Shift in MOCVD-grown (Al, In)GaN Thin Films

2000 ◽  
Vol 5 (S1) ◽  
pp. 796-802 ◽  
Author(s):  
Yong-Hoon Cho ◽  
G. H. Gainer ◽  
J. B. Lam ◽  
J. J. Song ◽  
W Yang ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Stokes Shift ◽  
Energy Shift ◽  
Peak Position ◽  
Time Resolved ◽  
Temperature Range ◽  
Al Content ◽  
Peak Energy ◽  
Emission Behavior ◽  
Pl Intensity

We present a comprehensive study of the optical characteristics of (Al, In)GaN epilayers measured by photoluminescence (PL), integrated PL intensity, and time-resolved PL spectroscopy. For not only InGaN, but also AlGaN epilayers with large Al content, we observed an anomalous PL temperature dependence: (i) an “S-shaped” PL peak energy shift (decrease-increase-decrease) and (ii) an “inverted S-shaped” full width at half maximum (FWHM) change (increase-decrease-increase) with increasing temperature. Based on time-resolved PL, the S shape (inverted S shape) of the PL peak position (FWHM) as a function of temperature, and the much smaller PL intensity decrease in the temperature range showing the anomalous emission behavior, we conclude that strong localization of carriers occurs in InGaN and even in AlGaN with rather high Al content. We observed that the following increase with increasing Al content in AlGaN epilayers: (i) a Stokes shift between the PL peak energy and the absorption edge, (ii) a redshift of the emission with decay time, (iii) the deviations of the PL peak energy, FWHM, and PL intensity from their typical temperature dependence, and (iv) the corresponding temperature range of the anomalous emission behavior. This indicates that the band-gap fluctuation responsible for these characteristics is due to energy tail states caused by non-random inhomogeneous alloy potential variations enhanced with increasing Al content.

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