Strong influence of SiO2 thin film on properties of GaN epilayers

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High-density plasma-induced etch damage of InGaN/GaN multiple quantum well light-emitting diodesThe effects of plasma etching on 1/f noise and photoluminescence ͑PL͒ characteristics of n-GaN have been investigated. A reduction of 1/f noise was observed after plasma exposure, a result of enhanced passivation of the reactive surface. This is attributed to the removal of carbon and the creation of a Ga-rich surface by the etching process. Nevertheless, the formation of nonradiative recombination centers impaired the PL intensity. Reconstruction of a stoichiometric surface was achieved by annealing. This induced the incorporation of carbon into GaN, deteriorating the PL performance further, but it could be restored by a chemical treatment of 10:1 HF:H 2 O.

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confidence: 99%

Plasma-induced damage to n-type GaN

Choi

Chua

Raman

et al. 2000

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“…12 Recent investigation, however, reveals that deposited SiO 2 can result in a significant degradation of the photoluminescence ͑PL͒ intensity due to the incorporation of oxygen as nonradiative recombination centers in GaN. 13 In comparison, deposition of Si x N y has found no improvement on the PL performance of GaN at all. Gallium oxide, characterized by the low refractive index and high static dielectric constant, has therefore become a promising candidate for resolving the issues of surface passivation on GaN.…”

Section: ͓S0003-6951͑00͒00704-x͔mentioning

confidence: 99%

Photoenhanced wet oxidation of gallium nitride

Peng¹,

Liao²,

Hsu³

et al. 2000

We investigate the photo-oxidation process and the corresponding passivation effects on the optical properties of unintentionally doped n-type gallium nitride (GaN). When illuminated with a 253.7 nm mercury line source, oxidation of GaN is found to take place in aqueous phosphorus acid solutions with pH values ranging from 3 to 4. At room temperature, the photo-oxidation process is found reaction-rate limited and has a peak value of 224 nm/h at pH=3.5. Compared with the as-grown GaN layers, threefold enhancement in the photocurrent and photoluminescence response are observed on the oxidized GaN surfaces. These results are attributed to the surface passivation effects due to the deep ultraviolet-enhanced wet oxidation on GaN.

“…Foreign dielectrics such as SiO 2 and Si 3 N 4 demonstrate limited improvement of the GaN properties. 11 However, PEC grown oxide layers give rise to enhanced band edge photoluminescence ͑PL͒ and intrinsic photoconductivity ͑PC͒, suggesting passivation of the GaN surface. 8 The exact mechanism remains unresolved.…”

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confidence: 99%

Effect of photoelectrochemical oxidation on properties of GaN epilayers grown by molecular beam epitaxy

Kang

Yuldashev

et al. 2001

Articles you may be interested inEffect of growth temperature on defects in epitaxial GaN film grown by plasma assisted molecular beam epitaxy AIP Advances 4, 027114 (2014); 10.1063/1.4866445Deep traps in n-type GaN epilayers grown by plasma assisted molecular beam epitaxy GaN epilayers grown by molecular beam epitaxy were photoelectrochemically ͑PEC͒ oxidized in an aqueous KOH solution. The oxidation effect was investigated by defect-related photoconductivity and photoluminescence. The PEC treated GaN show decreased extrinsic photoresponse and concentration of deep level states in comparison with the as-grown sample. The PEC process also results in enhanced donor-bound exciton photoluminescence at 3.47 eV and restrained 3.4 eV band. No strain is detected in the PEC oxidized GaN. The 3.4 eV band is related to structural defects instead of oxygen impurities. Rather, the defects can be passivated by the PEC oxidation.