scholarly journals Comment on ‘‘A study of cathode edge emission’’

1984 ◽  
Vol 55 (3) ◽  
pp. 792-793 ◽  
Author(s):  
J. Hasker
Keyword(s):  
1995 ◽  
Vol 395 ◽  
Author(s):  
D.A.S. Loeber ◽  
J.M. Redwing ◽  
N.G. Anderson ◽  
M.A. Tischler

ABSTRACTEdge emission characteristics of optically pumped GaN-AlGaN double heterostructures and quantum wells are examined. The samples, which were grown by metalorganic vapor phase epitaxy, are photoexcited with light from a pulsed nitrogen laser. The pump light is focused to a narrow stripe on the sample surface, oriented perpendicular to a cleaved edge, and the edge luminescence is collected and analyzed. We first compare emission characteristics of highly excited GaN-AlGaN double heterostructures grown simultaneously on SiC and sapphire substrates. Polarization resolved spectral properties of edge luminescence from both structures is studied as a function of pump intensity and excitation stripe length. Characteristics indicative of stimulated emission are observed, particularly in the sample grown on SiC. We then present results demonstrating laser emission from a GaN-AlGaN separate-confinement quantum-well heterostructure. At high pump intensities, band edge emission from the quantum well exhibits five narrow (∼1 Å) modes which are evenly spaced by 10Å to within the resolution of the spectrometer. This represents the first demonstration of laser action in a GaN-based quantum-well structure.


1959 ◽  
Vol 30 (8) ◽  
pp. 1135-1140 ◽  
Author(s):  
R. J. Collins
Keyword(s):  

1964 ◽  
Vol 15 (9) ◽  
pp. 1127-1129 ◽  
Author(s):  
G W Bradberry ◽  
W E Spear

1960 ◽  
Vol 120 (3) ◽  
pp. 840-842 ◽  
Author(s):  
R. J. Collins ◽  
J. J. Hopfield
Keyword(s):  

2007 ◽  
Vol 137 (1-3) ◽  
pp. 156-161 ◽  
Author(s):  
S. Kondo ◽  
T. Saito ◽  
H. Asada ◽  
H. Nakagawa

MRS Advances ◽  
2018 ◽  
Vol 3 (56) ◽  
pp. 3293-3299 ◽  
Author(s):  
Niraj Shrestha ◽  
Corey R. Grice ◽  
Ebin Bastola ◽  
Geethika K. Liyanage ◽  
Adam B. Phillips ◽  
...  

We present the defect analysis by photoluminescence (PL) spectroscopy of CdSexTe1-x thin films, grown with varying Se content by a co-sputtered deposition method. We observe a peak at 1.203 eV in the CdSexTe1-x film for x = 0.21, which shifts towards higher energies with increase in laser power. This peak was assigned to a donor-to-acceptor (DAP) transition, with a measured j-shift of ∼4.7 meV/decade. Temperature dependent PL intensity measurements confirm that the observed DAP peak involves a shallow defect state of binding energy ∼34.7 meV. In contrast, a free-to-bound (FB) peak at 1.294 eV involving a shallow defect of binding energy ∼18.3 meV was observed in the CdSexTe1-x film for x = 0.14. Additionally, we observe band edge emission at 1.452 eV and 1.448 eV in CdSexTe1-x films for x = 0.14 and x = 0.21 respectively. Our analysis shows that the Se concentration not only changes the band gap energy of the resulting CdSexTe1-x alloy thin film, but also modifies the nature of the dominant observed defect emission.


1990 ◽  
Vol 5 (11) ◽  
pp. 2507-2514 ◽  
Author(s):  
A. T. Collins ◽  
M. Kamo ◽  
Y. Sato

Absorption and cathodoluminescence spectra have been recorded for single crystals of diamond and polycrystalline films of diamond, grown by microwave-assisted chemical vapor deposition (CVD) using methane and hydrogen. The investigation has been carried out to see to what extent the properties of CVD diamond are similar to those of conventional diamond, and to what extent they are unique. Studies have been made of the as-grown material, which has not been intentionally doped, and also samples that have been subjected to radiation damage and thermal annealing. The single crystals grown using methane concentrations of 0.5 to 1.0% exhibit bright blue “band A” emission and also intense edge emission, similar to the cathodoluminescence spectra of some natural type IIa diamonds. This implies that the crystals are relatively free from structural and chemical defects, a conclusion which is reinforced by the absence of any zero-phonon lines in the absorption spectra of crystals which have been subjected to radiation damage and annealing at 800 °C. Before radiation damage the spectrum does, however, reveal an absorption which increases progressively to higher energies, and which may be associated with sp2-bonded carbon. The Cathodoluminescence spectra after radiation damage indicate that the crystals contain some isolated nitrogen, and the detection of H3 luminescence, following thermal annealing at 800 °C, demonstrates for the first time that these samples contain small concentrations of nitrogen pairs. All of the polycrystalline films, grown using methane concentrations between 0.3 and 1.5%, have an absorption which increases progressively to higher energies, and which again is attributed to sp2-bonded carbon. This absorption is stronger in the films grown using higher methane concentrations. Films grown at a methane concentration of 0.3% also exhibit bright blue cathodoluminescence, although the edge emission is undetectably weak. The use of higher methane concentrations produces films with evidence in the cathodoluminescence spectra of nitrogen + vacancy and nitrogen + interstitial complexes, as well as optical centers unique to CVD diamond. One particular defect produces an emission and absorption line at 1.681 eV. By implanting conventional diamonds with 29Si ions it has been confirmed that this center involves silicon, and it has been shown that the 1.681 eV luminescence is relatively more intense in implanted diamonds which have a high concentration of isolated nitrogen.


1969 ◽  
Vol 178 (3) ◽  
pp. 1310-1318 ◽  
Author(s):  
P. J. Dean ◽  
J. L. Merz
Keyword(s):  

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