Photoluminescence of erbium-implanted GaN and in situ-doped GaN:Er

Abstract

The photoluminescence of in situ-doped GaN:Er during hydride vapor phase epitaxy was compared to an Er-implanted GaN sample. At 11 K, the main emission wavelength of the in situ-doped sample is shifted to shorter wavelengths by 2.5 nm and the lifetime is 2.1Ϯ0.1 ms as compared to 2.9Ϯ0.1 ms obtained for the implanted sample. The 295 K band edge luminescence of the in situ-doped sample was free of the broad band luminescence centered at 500 nm which dominated the spectrum of the implanted sample. Reversible changes in the emission intensity of the in situ-doped sample upon annealing in a N 2 versus a NH 3 /H 2 ambient indicate the probable role of hydrogen in determining the luminescence efficiency of these samples. © 1998 American Institute of Physics. ͓S0003-6951͑98͒02010-5͔The rare-earth element erbium in the trivalent state (Er 3ϩ ) has received considerable attention since the 4 I 13/2 → 4 I 15/2 transition at 1540 nm coincides with a minimum in loss in silica optical fibers.1 This transition occurs between energy levels within the shielded 4 f electron shell, making the optical transitions of Er 3ϩ sharp, as well as relatively insensitive to temperature and host affects.2 These luminescence properties make erbium-doped semiconductors an appealing material system for application in optoelectronic devices.One problem which plagues the development of a practical erbium-doped semiconductor device is the pronounced temperature quenching of the rare-earth luminescence within most semiconductor hosts. Favennec et al. discovered that quenching of the rare-earth luminescence was reduced in wide band-gap semiconductor hosts.3 This discovery has lead to several investigations of Er-implanted GaN. [4][5][6][7][8][9][10][11][12] GaN is a wide band-gap III-V semiconductor useful as a short wavelength emitter and detector. 13 Previous investigations of Er luminescence in GaN:Er have been promising with most researchers finding only an ϳ50% decrease in photoluminescence intensity over the temperature range 6-300 K. 4,8,9,11 This is a significant improvement over the two-to-three order of magnitude decrease of Er luminescence intensity in GaAs:Er. 2The studies performed on GaN:Er so far have principally focused on Er implanted into GaN. The large mass of the Er implant species limits this technique to the formation of thin layers of GaN:Er with a high amount of residual implantrelated damage. In this letter, we report a photoluminescence study of in situ-doped GaN:Er during hydride vapor phase epitaxy ͑HVPE͒ using elemental Er as the in situ dopant and Er implanted into nominally undoped GaN also grown by HVPE. HVPE is an established technique for GaN growth and is capable of providing high growth rates and thick GaN layers. 13,14 The in situ doping of GaN with Er during HVPE growth should result, therefore, in thick, uniformly doped layers. Low temperature Er 3ϩ luminescence of the in situdoped sample is observed with the peak intensity at 1536.5 nm and an 11 K lifetime of 2.1Ϯ0.1 ms. The Er 3ϩ luminescence was no lon...

Photoluminescence and Photoluminescence Excitation Spectroscopy of in Situ Er-Doped and Er-Implanted GaN Films Grown by Hydride Vapor Phase Epitaxy

“…A peak Er concentration of 2 x 10 19 ions/cm 3 was achieved in this in situ Er-doped GaN at a thickness of 1000 nm [7]. The GaN films grown on sapphire by HVPE were implanted with a dosage of 2 x 10 14 ions/cm 2 at 300 keV.…”

“…The GaN films grown on sapphire by HVPE were implanted with a dosage of 2 x 10 14 ions/cm 2 at 300 keV. The peak concentration of Er is 5.3 x 10 19 ions/cm 3 at a depth of 33 nm [7]. These Er-implanted HVPE-grown GaN films were annealed in a conventional tube furnace at 800 o C for 30 minutes in a flowing NH 3 /H 2 .…”

“…Site-selective PL and PLE spectroscopies used in our previous work are applied in this study to Er-implanted hydride vapor phase epitaxy (HVPE)-grown GaN annealed at 800 o C in an NH 3 /H 2 atmosphere and in situ Er-doped HVPE-grown GaN [7] to see if any of the seven different Er 3+ sites observed in Er-implanted MOCVD-grown GaN exist in these samples. The PLE and PL of these two different HVPE-grown samples are compared here first with the Erimplanted MOCVD-grown sample and then the differences and similarities among the siteselective PLE and PL spectra of these three different Er-doped GaN films are discussed in detail.…”

“…Photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy have been performed to study the different structural configurations (sites or centers) on which Er 3+ ions are incorporated in Er-doped GaN and to investigate their excitation mechanisms [1][2][3][4][5][6][7]. Our previous study of site-selective PL and PLE spectroscopy in Er-implanted samples of GaN grown by metal organic chemical vapor deposition (MOCVD) that were annealed at 900 o C under a flow of N 2 revealed the existence of seven different Er 3+ sites [3].…”

Visible and Infrared Rare-Earth Activated Electroluminescence From Erbium Doped GaN

“…III-V semiconductors doped with rare-earth elements have also been used 10,11,12,13,14,15,16,17,18 and have advantages compared to narrow bandgap materials 19 . The advantage of Nakamura's devices is their extremely high quantum efficiency 1 (~5%), whereas RE doped devices offer multiple color emission, wavelength-limited only by the RE element(s) chosen and not by the band gap energy of the semiconductor.…”