Lattice Location and Photoluminescence of Er in GaAs and Al0.5Ga0.5As

1993 ◽  
Vol 301 ◽  
Author(s):  
E. Alves ◽  
M.F. Da Silva ◽  
A. A. Melo ◽  
J.C. Soares ◽  
G.N. Van Den Hoven ◽  
...  

ABSTRACTEpitaxial Er-doped GaAs and Al0.5Ga0.5As films, 1.6 μm thick, grown by MBE on (100) GaAs substrates at 560°C, with Er concentrations in the range 9 × 1017 to 2 × 1020 cm−3 were studied with RBS/channeling and photoluminescence techniques. Angular scans in the <110> and <111> axial and (111) planar directions indicate that the Er atoms in GaAs are located on interstitial sites. In Al0.5Ga0.5As doped with 5 × 1019 Er cm−3, 70% of the Er atoms are on positions slightly displaced from the interstitial site, the rest presumably substitutional. In Al0.5Ga0.5As doped with 9 × 19 Er cm−3, more than 88% of the Er atoms are on substitutional sites.Photoluminescence around 1.54 μm is observed at room-temperature in Er-doped Al0.5Ga0.5As. Both the low and highly Er-doped samples show similar luminescence intensities; the luminescence lifetimes are on the order of 1 ms. The Er-doped GaAs does not show any measurable signal at room-temperature. Correlation of the luminescence data to the Er lattice location suggests that only substitutional Er in AlGaAs is in the luminescent trivalent state.

1993 ◽  
Vol 301 ◽  
Author(s):  
S. J. Chang ◽  
K. Takahei ◽  
J. Nakata ◽  
Y. K. Su

ABSTRACTWe report the first study of impact excitation of Er ions in GaAs. The MOCVDgrown, p+-n structured EL devices were fabricated by growing, at different temperatures, GaAs:Er layers on top of the n+ GaAs substrates. P+ layers were made by Zn diffusion from the top surfaces. When we forward biased these diodes, their EL spectra were similar to their respective PL spectra for each sample but different from each other's. However, when we reverse biased these diodes, EL spectra obtained from all samples are the same, which were different from their PL spectra. These results indicate that the Er center(s) excited by direct impact is different from the Er center(s) excited through electron-hole recombination and subsequent energy transfer. By using RBS channeling, we found that most of the Er ions, in our MOCVD-grown GaAs:Er samples, occupy a displaced tetrahedral interstitial site. From these PL, EL and RBS results, we conclude that only a small amount of Er ions emit luminescence when they are indirectly excited through energy transfer.


1998 ◽  
Vol 227-230 ◽  
pp. 1164-1167 ◽  
Author(s):  
Oleg Gusev ◽  
Mikhail Bresler ◽  
Alexey Kuznetsov ◽  
Vera Kudoyarova ◽  
Petr Pak ◽  
...  

1999 ◽  
Vol 595 ◽  
Author(s):  
U. Hömmerich ◽  
J. T. Seo ◽  
J. D. MacKenzie ◽  
C. R. Abernathy ◽  
R. Birkhahn ◽  
...  

AbstractWe report on the luminescence properties of Er doped GaN grown prepared by metalorganic molecular beam epitaxy (MOMBE) and solid-source molecular beam epitaxy (SSMBE) on Si substrates. Both types of samples emitted characteristic 1.54 µm PL resulting from the intra-4f Er3+ transition 4I13/2→4I15/2. Under below-gap excitation the samples exhibited very similar 1.54 µm PL intensities. On the contrary, under above-gap excitation GaN: Er (SSMBE) showed ∼80 times more intense 1.54 µm PL than GaN: Er (MOMBE). In addition, GaN: Er (SSMBE) also emitted intense green luminescence at 537 nm and 558 nm, which was not observed from GaN: Er (MOMBE). The average lifetime of the green PL was determined to be 10.8 µs at 15 K and 5.5 µs at room temperature. A preliminary lifetime analysis suggests that the decrease in lifetime is mainly due to the strong thermalization between the 2H11/2 and 4S3/2 excited states. Nonradiative decay processes are expected to only weakly affect the green luminescence.


1998 ◽  
Vol 536 ◽  
Author(s):  
Se-Young Seo ◽  
Jung H. Shin ◽  
Choochon Lee

AbstractThe photoluminescent properties of erbium doped silicon rich silicon oxide (SRSO) is investigated. The silicon content of SRSO was varied from 43 to 33 at. % and Er concentration was 0.4–0.7 at. % in all cases. We observe strong 1.54 μ m luminescence due to 4I13/2⇒4I15/2 Er3+ 4f transition, excited via energy transfer from carrier recombination in silicon nanoclusters to Er 4f shells. The luminescent lifetimes at the room temperature are found to be 4–7 msec, which is longer than that reported from Er in any semiconducting host material, and comparable to that of Er doped SiO2 and A12O3. The dependence of the Er3+ luminescent intensities and lifetimes on temperature, pump power and on background illumination shows that by using SRSO, almost all non-radiative decay paths of excited Er3+ can be effectively suppressed, and that such suppression is more important than increasing excitation rate of Er3+. A planar waveguide using Er doped SRSO is also demonstrated.


2000 ◽  
Vol 650 ◽  
Author(s):  
Eduardo J. Alves ◽  
C. Liu ◽  
Maria F. da Silva ◽  
José C. Soares ◽  
Rosário Correia ◽  
...  

ABSTRACTIn this work we report the structural and optical properties of ion implanted GaN. Potential acceptors such as Ca and Er were used as dopants. Ion implantation was carried out with the substrate at room temperature and 550 °C, respectively. The lattice site location of the dopants was studied by Rutherford backscattering/channeling combined with particle induced X-ray emission. Angular scans along both [0001] and [1011] directions show that 50% of the Er ions implanted at 550 oC occupy substitutional or near substitutional Ga sites after annealing. For Ca we found only a fraction of 30% located in displaced Ga sites along the [0001] direction. The optical properties of the ion implanted GaN films have been studied by photoluminescence measurements. Er- related luminescence near 1.54 μm is observed under below band gap excitation at liquid helium temperature. The spectra of the annealed samples consist of multiline structures with the sharpest lines found in GaN until now. The green and red emissions were also observed in the Er doped samples after annealing.


1996 ◽  
Vol 68 (8) ◽  
pp. 1126-1128 ◽  
Author(s):  
G. M. Ford ◽  
B. W. Wessels
Keyword(s):  

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