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Full-Text Articles in Physics
Photoluminescence From Gan Co-Doped With C And Si, Mykhailo Vorobiov
Photoluminescence From Gan Co-Doped With C And Si, Mykhailo Vorobiov
Theses and Dissertations
This thesis devoted to the experimental studies of yellow and blue luminescence (YL and BL relatively) bands in Gallium Nitride samples doped with C and Si. The band BLC was at first observed in the steady-state photoluminescence spectrum under high excitation intensities and discerned from BL1 and BL2 bands appearing in the same region of the spectrum. Using the time-resolved photoluminescence spectrum, we were able to determine the shape of the BLC and its position at 2.87 eV. Internal quantum efficiency of the YL band was estimated to be 90\%. The hole capture coefficient of the BLC …
Study Of The Photoluminescence Spectra Of Mg-Doped Gan, Puranjan Ghimire
Study Of The Photoluminescence Spectra Of Mg-Doped Gan, Puranjan Ghimire
Theses and Dissertations
We have studied luminescence properties of Mg-doped GaN grown by hydride vapor phase epitaxy. Steady state photoluminescence (PL) spectra have been analyzed. Exciton, ultraviolet luminescence (UVL) and blue luminescence (BL) bands are the dominant PL bands in the spectra. At low temperature, Exciton and UVL bands show almost no shift with excitation intensity, whereas the BL band blueshifts by almost 0.4 ���� with increasing excitation intensity by seven orders of magnitude. Such shifting nature of bands with excitation intensity is explained by assuming that the BL band is detected from the region of the sample where potential fluctuations are very …
Thermal Quenching Of Photoluminescence In Zno And Gan, Nahla Albarakati
Thermal Quenching Of Photoluminescence In Zno And Gan, Nahla Albarakati
Theses and Dissertations
Investigation of the thermal quenching of photoluminescence (PL) in semiconductors provides valuable information on identity and characteristics of point defects in these materials, which helps to better understand and improve the properties of semiconductor materials and devices. Abrupt and tunable thermal quenching (ATQ) of PL is a relatively new phenomenon with an unusual behavior of PL. This mechanism was able to explain what a traditional model failed to explain. Usually, in traditional model used to explain “normal” quenching, the slope of PL quenching in the Arrhenius plot determines the ionization energy of the defect causing the PL band. However, in …
Time-Resolved Photoluminescence Studies Of Point Defects In Gan, Joy Dorene Mcnamara
Time-Resolved Photoluminescence Studies Of Point Defects In Gan, Joy Dorene Mcnamara
Theses and Dissertations
Time-resolved photoluminescence (TRPL) measurements paired with steady-state photoluminescence (SSPL) measurements can help to determine the PL lifetime, shape and position of unresolved bands, capture coefficients, and concentrations of free electrons and defects.PL bands that are obscured in the SSPL spectra can be accurately revealed by TRPL measurements. TRPL measurements are able to show if the PL band originates from an internal transition between different states of the same defect. The main defect-related PL bands in high-purity GaN grown by hydride vapor phase epitaxy (HVPE) which have been investigated are the ultraviolet, blue, green, yellow and red luminescence bands (UVL, BL, …
Beyond Conventional C-Plane Gan-Based Light Emitting Diodes: A Systematic Exploration Of Leds On Semi-Polar Orientations, Morteza Monavarian
Beyond Conventional C-Plane Gan-Based Light Emitting Diodes: A Systematic Exploration Of Leds On Semi-Polar Orientations, Morteza Monavarian
Theses and Dissertations
Despite enormous efforts and investments, the efficiency of InGaN-based green and yellow-green light emitters remains relatively low, and that limits progress in developing full color display, laser diodes, and bright light sources for general lighting. The low efficiency of light emitting devices in the green-to-yellow spectral range, also known as the “Green Gap”, is considered a global concern in the LED industry. The polar c-plane orientation of GaN, which is the mainstay in the LED industry, suffers from polarization-induced separation of electrons and hole wavefunctions (also known as the “quantum confined Stark effect”) and low indium incorporation efficiency that …
The Effect Of Temperature On The Electrical And Optical Properties Of P-Type Gan, Joy Mcnamara
The Effect Of Temperature On The Electrical And Optical Properties Of P-Type Gan, Joy Mcnamara
Theses and Dissertations
The development of gallium nitride (GaN) light emitting devices has reached extraordinary echelons. As such, the characterization and analysis of the behavior of GaN materials is essential to the advancement of GaN technology. In this thesis, the effect of temperature on the optical and electrical properties of p-type GaN is investigated. The GaN samples used in this work were grown by various methods and studied by Kelvin probe and photoluminescence (PL) techniques. Specifically, the surface photovoltage (SPV) behavior and PL data were analyzed at different temperatures and illumination intensities. Using the SPV results, we show that p-type GaN exhibits n-type …
Thermal Quenching Of Photoluminescence From Gan, Anita Olsen
Thermal Quenching Of Photoluminescence From Gan, Anita Olsen
Theses and Dissertations
GaN is a III-V semiconductor that is a promising material used in production of light emitting devices and high power/high frequency electronics. The electronic and optical properties of GaN are subdued by defects that occur during the growth processes of this material. The emitted photoluminescence (PL) from optically excited GaN gives insight into the origins and effects of point defects within the crystal lattice structure of GaN. In this study, PL spectroscopy is used to examine and analyze the point defects that occur in Zn-doped GaN. The blue luminescence band seen in undoped and Zn-doped GaN have identical fine structure …