Electronic states of deep trap levels in a-plane GaN templates grown on r-plane sapphire by HVPE

Lee, Moonsang; Vu, Thi Kim Oanh; Lee, Kyoung Su; Kim, Eun Kyu

doi:10.1038/s41598-018-26290-y

Cited by 9 publications

(3 citation statements)

References 30 publications

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“…[35] Actually, it has been reported that the a-plane GaN grown on r-face sapphire by hydride vapor phase epitaxy as well as some other types of as-grown GaN exhibit similar strong yellow light emission. [36] In our case, upon increasing irradiation fluences, such a yellow emission is gradually suppressed, as shown in Fig. 7.…”

Section: Resultssupporting

confidence: 66%

Structure and luminescence of a-plane GaN on r-plane sapphire substrate modified by Si implantation*

Huang¹,

Li²,

Shang³

et al. 2021

Chinese Phys. B

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We show the structural and optical properties of non-polar a-plane GaN epitaxial films modified by Si ion implantation. Upon gradually raising Si fluences from 5 × 1013 cm−2 to 5 × 1015 cm−2, the n-type dopant concentration gradually increases from 4.6 × 1018 cm−2 to 4.5 × 1020 cm−2, while the generated vacancy density accordingly raises from 3.7 × 1013 cm−2 to 3.8 × 1015 cm−2. Moreover, despite that the implantation enhances structural disorder, the epitaxial structure of the implanted region is still well preserved which is confirmed by Rutherford backscattering channeling spectrometry measurements. The monotonical uniaxial lattice expansion along the a direction (out-of-plane direction) is observed as a function of fluences till 1 × 1015 cm−2, which ceases at the overdose of 5 × 1015 cm−2 due to the partial amorphization in the surface region. Upon raising irradiation dose, a yellow emission in the as-grown sample is gradually quenched, probably due to the irradiation-induced generation of non-radiative recombination centers.

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Section: Resultssupporting

confidence: 66%

Structure and luminescence of a-plane GaN on r-plane sapphire substrate modified by Si implantation*

Huang¹,

Li²,

Shang³

et al. 2021

Chinese Phys. B

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“…The activation energy and capture cross-section of the defects were calculated using the emission rate equation [31,32]:…”

Section: Dlts Resultsmentioning

confidence: 99%

Electrical characterization of Au/Ni Schottky contacts on GaN synthesized using electrodeposition

Ali

Omotoso²,

Nel³

et al. 2023

Semicond. Sci. Technol.

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Gallium nitride thin films have attracted attention due to their prospects in semiconductor devices and technology. In this study, we investigate the electrical properties and perform deep level transient spectroscopy (DLTS) on Au/Ni Schottky diodes fabricated on gallium nitride thin films that were synthesized by electrodeposition on a Si (111) substrate from a solution containing gallium nitrate (Ga(NO3)3) and ammonium nitrate (NH4(NO3)) using current densities of 1 and 3 mA/cm2. The thin films were found to crystalize in the wurtzite hexagonal structure with crystallite sizes of approximately 20 nm. Scanning electron microscopy and atomic force microscopy were used to characterize the microstructure of the GaN thin films. The Schottky diodes had good rectifying properties, corresponding to n-type material. The diodes had a IV barrier heights of 0.76 eV and 0.60 eV; a CV barrier heights of 0.92 eV and 0.71 eV; and carrier densities of 1.2 × 1016 cm-3, and 1.7 × 1016 cm-3, for material deposited under 1 mA/cm2 and 3 mA/cm2, respectively. By fitting a model taking both thermionic emission as well as conduction through the polycrystalline bulk into account, it was found that the grain boundary potential of the GaN crystallites was 0.29 V. The DLTS study revealed different dominant DLTS peaks in each as-grown sample with activation energies of 0.49 and 0.48 eV with capture cross-sections of 9 × 10-15 and 4 × 10-16 cm2, in the material grown under 1 mA/cm2 and 3 mA/cm2 current density, respectively. The defects seem to be similar to defects found in heavily damaged GaN and GaN grown on highly mismatched or cracked substrates, and are probably not simple defects.

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“…Nevertheless, short carrier decay lifetimes in the high resistivity HVPE GaN materials might be beneficial in the fabrication of fast response and ionising-radiation-sensitive, but solar-blind, detectors. Complementarily, HVPE growth of the non-polar GaN [66] is promising to avoid complications in formation of the reliable contacts and junctions where piezo-and spontaneous polarization effects can be negligible.…”

Section: Discussionmentioning

confidence: 99%

Electrical characterization of HVPE GaN containing different concentrations of carbon dopants

Gaubas

Čeponis

Deveikis

et al. 2018

Semicond. Sci. Technol.

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A comprehensive study of the electrical characteristics in Schottky diodes made of GaN:C grown by hydride vapour phase epitaxy (HVPE) technology has been reported. The Schottky junctions were made of an Ni/Au (25/200 nm) metal stack and ohmic contacts were fabricated by Ti/Al/ Ni/Au (30/90/20/100 nm) e-beam deposition of the metal thin-films followed by rapid thermal annealing. A good quality of the fabricated Schottky diodes has been proved by considering the transient shape using a pulsed technique of barrier evaluation under linearly increasing voltage (BELIV). The concentrations of equilibrium carriers of 1×10 11 cm −3 and of 2×10 10 cm −3 have been evaluated for relatively low and high carbon density doped samples, respectively, using photocapacitance characteristics dependent on excitation intensity. The effective mobility of carriers of μ eff =610 cm 2 /Vs has been estimated by considering the serial resistance variations dependent on excitation density, through analysis of delay times that appeared in the formation of peaks within BELIV transients. Optical deep level transient spectroscopy has shown that thermal emission from the rather shallow centres prevails. The centres, ascribed to vacancies as well as to carbon on Ga sites, have been identified. It has been demonstrated that Schottky junctions made of heavy carbon doped (N C 10 18 cm −3 ) HVPE GaN material are able to withstand voltages of 300 V.

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Electronic states of deep trap levels in a-plane GaN templates grown on r-plane sapphire by HVPE

Cited by 9 publications

References 30 publications

Structure and luminescence of a-plane GaN on r-plane sapphire substrate modified by Si implantation*

Structure and luminescence of a-plane GaN on r-plane sapphire substrate modified by Si implantation*

Electrical characterization of Au/Ni Schottky contacts on GaN synthesized using electrodeposition

Electrical characterization of HVPE GaN containing different concentrations of carbon dopants

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