| 1. |
- Hashemi, Seyed Ehsan, 1986, et al.
(författare)
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Effect of compositional interlayers on the vertical electrical conductivity of Si-doped AlN/GaN distributed Bragg reflectors grown on SiC''
- 2017
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Ingår i: Applied Physics Express. - 1882-0786 .- 1882-0778. ; 10:5, s. 055501-
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the effect of strain-compensating interlayers on the vertical electrical conductivity of Si-doped AlN/GaN distributed Bragg reflectors (DBRs). Samples with 10.5 mirror pairs were grown through plasma-assisted molecular beam epitaxy on SiC. Room-temperature current–voltage characteristics were measured vertically in mesas through 8 of the 10.5 pairs. The sample with no interlayers yields a mean specific series resistance of 0.044 Ω cm2 at low current densities, while three samples with 5/5-Å-thick, 2/2-nm-thick, and graded interlayers have resistivities between 0.16 and 0.34 Ω cm2. Thus, interlayers impair vertical current transport, and they must be designed carefully when developing conductive DBRs.
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| 2. |
- Hjort, Filip, 1991, et al.
(författare)
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Vertical Electrical Conductivity of ZnO/GaN Multilayers for Application in Distributed Bragg Reflectors
- 2018
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Ingår i: IEEE Journal of Quantum Electronics. - 0018-9197 .- 1558-1713. ; 54:4
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Tidskriftsartikel (refereegranskat)abstract
- We have demonstrated an electrically conductive ZnO/GaN multilayer structure using hybrid plasma-assisted molecular beam epitaxy. Electrical I-V characteristics were measured through the top three pairs of a six pair ZnO/GaN sample. The total measured resistance was dominated by lateral and contact resistances, setting an upper limit of similar to 10(-4) Omega.cm(2) for the vertical specific series resistance of the stack. A strong contribution to the low resistance is the cancellation of spontaneous and piezoelectric polarization that occurs in the in- plane strained ZnO/GaN sample, as shown by electrical simulations. In addition, the simulations show that the actual vertical resistance of the sample could in fact be three orders of magnitude lower and that ZnO/GaN structures with thicknesses fulfilling the Bragg condition should have similar resistance. Our results suggest that ZnO/GaN distributed Bragg reflectors (DBRs) are a promising alternative to pure III-nitride DBRs in GaN-based vertical-cavity surface-emitting lasers.
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| 3. |
- Sun, Jie, 1977, et al.
(författare)
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Direct Chemical Vapor Deposition of Large-Area Carbon Thin Films on Gallium Nitride for Transparent Electrodes: A First Attempt
- 2012
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Ingår i: IEEE Transactions on Semiconductor Manufacturing. - : Institute of Electrical and Electronics Engineers (IEEE). - 0894-6507 .- 1558-2345. ; 25:3, s. 494-501
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Tidskriftsartikel (refereegranskat)abstract
- Direct formation of large-area carbon thin films on gallium nitride by chemical vapor deposition without metallic catalysts is demonstrated. A high flow of ammonia is used to stabilize the surface of the GaN (0001)/sapphire substrate during the deposition at 950 degrees C. Various characterization methods verify that the synthesized thin films are largely sp(2) bonded, macroscopically uniform, and electrically conducting. The carbon thin films possess optical transparencies comparable to that of exfoliated graphene. This paper offers a viable route toward the use of carbon-based materials for future transparent electrodes in III-nitride optoelectronics, such as GaN-based light emitting diodes and laser diodes.
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