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| 3. |
- Harati Zadeh, Hamid, 1964-, et al.
(författare)
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Photoluminescence study of Si-doped GaN/Al0.07Ga0.93N multiple quantum wells with different dopant position
- 2004
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 84:25, s. 5071-5073
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Tidskriftsartikel (refereegranskat)abstract
- The Si-doped GaN/Al0.07Ga0.93N multiple quantum wells (MQW) were investigated, using photoluminescence (PL) and time-resolved (PL) measurements. The influence of Si doping on the emission energy and recombination dynamics of the MWQs were also investigated, with different dopant position in the wells. It was observed that the redshifted emission of the MQWs was attributed to the self-energy shift of the electron states due to the correlated motion of the electrons exposed to the fluctuating potential of the donor ions. It was also observed that the PL decay time of the sample was ∼760 ps, at low temperature.
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| 4. |
- Kasic, A., et al.
(författare)
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Characterization of crack-free relaxed GaN grown on 2″ sapphire
- 2005
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 98:7, s. 73525-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the growth of high-quality and virtually strain-free bulklike GaN by hydride vapor-phase epitaxy in a vertical atmospheric-pressure reactor with a bottom-fed design. The 300‐μm-thick GaN layer was grown on a 2″ (0 0 0 1) sapphire substrate buffered with a ∼ 2‐μm-thick GaN layer grown by metal-organic chemical-vapor deposition. During the cool down process to room temperature, cracking was induced in the sapphire substrate, thereby allowing the bulklike GaN layer to relax without provoking cracking of itself. The crystalline quality and the residual strain in the 2″ GaN wafer were investigated by various characterization techniques. The lateral homogeneity of the wafer was monitored by low-temperature photoluminescence mapping. High-resolution x-ray diffraction and photoluminescence measurements proved the high crystalline quality of the material grown. The position of the main near-band-gap photoluminescence line and the phonon spectra obtained from infrared spectroscopic ellipsometry show consistently that the 2″ crack-free GaN is virtually strain-free over a diameter of approximately 4 cm.
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| 5. |
- Monemar, Bo, 1942-, et al.
(författare)
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Defect related issues in the "current roll-off" in InGaN based light emitting diodes
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 91, s. 181103-1-181103-3
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Tidskriftsartikel (refereegranskat)abstract
- Defect related contributions to the reduction of the internal quantum efficiency of InGaN-based multiple quantum well light emitting diodes under high forward bias conditions are discussed. Screening of localization potentials for electrons is an important process to reduce the localization at high injection. The possible role of threading dislocations in inducing a parasitic tunneling current in the device is discussed. Phonon-assisted transport of holes via tunneling at defect sites along dislocations is suggested to be involved, leading to a nonradiative parasitic process enhanced by a local temperature rise at high injection.
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| 6. |
- Yakimova, Rositsa, 1942-, et al.
(författare)
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Preface
- 2007
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Ingår i: First International Symposium on Growth of Nitrides ISGN-1,2006. - Journal of Crystal Growth, Vol. 300 : Elsevier Science.
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Konferensbidrag (refereegranskat)
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| 7. |
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Advances in Light emitting Materials
- 2008
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- This special-topic volume‚ Advances in Light-Emitting Materials’, makes an important contribution to the field of silicon and III-nitride semiconductors. It begins with a brief history of visible-light emitting diodes. However, silicon is currently expanding from micro-electronics and into photonics. Due to its unsuitable band-gap, it has not previously been the material-of-choice for opto-electronic integration. That is now beginning to change and silicon devices have been developed which have the capability to emit, modulate, guide and detect light and which can be combined with microelectronics to form electronic and photonic integrated circuits. read more...In particular, the performance of silicon-based light-emitters has made rapid progress during the last few years: the first paper describes the potential value of the D-band luminescence caused by dislocations in silicon and its use in infra-red light-emitters. Silicon-wafer direct-bonding, which permits the controlled formation of dislocation networks, is described in detail in the next paper. Silicon and silicon-germanium light-emitting diodes (LED), which emit band-to-band radiation, are then described. This paper is followed by observations on the effect of carrier-confinement on the emission of the band-to-band radiation of LEDs fabricated in silicon-on-insulator form. Finally, MOS light-emitting devices, based upon rare-earth ion-implantation, are described. These structures exhibit efficient electroluminescence within the wavelengths ranging from UV to visible light.Altogether, this volume presents an in-depth review of this important topic.
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