Dislocation density control of GaN epitaxial film and its photodetector

Li, Linhao; Yang, Yuhui; Chen, Guojie; Wang, Wenliang; Jiang, Hongsheng; Wang, Haiyan; Zhang, Chenguang; Kong, Deqi; Zhang, Jinghong; Luo, Zhengtang; Li, Guoqiang

doi:10.1016/j.vacuum.2021.110800

Cited by 11 publications

(3 citation statements)

References 34 publications

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“…The calculated screw dislocation densities are 5 10 8 cm -2 for S2 and 2.4 10 8 cm -2 for S1, which are the same magnitude as those previously reported [20]. Zhu et al [21] reported that the spectra of symmetric reflections (00.l) are broadened only by screw dislocations and the screw component of mixed dislocations, while those of asymmetric reflections are broadened by edge dislocations and the edge component of mixed dislocations.…”

Section: Resultssupporting

confidence: 84%

A study of the effects of SiN treatment on the GaN refractive index

Chalabi,

Laifi,

Bchetnia

et al. 2024

Preprint

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In the present study, both the GaN buffer layer approach and the sapphire SiN treatment method were used to develop GaN films by metalorganic chemical vapor deposition (MOCVD) on a c-plane (0001) sapphire substrate. The growth was controlled in situ by 632.8 nm laser reflectometry. The GaN-grown layer structure was investigated via high-resolution X-ray diffraction (HRXRD). The GaN structural properties improved upon SiN treatment. In addition, spectroscopic transmittance was used to determine the change in the bandgap energy of GaN upon SiN treatment. Spectroscopic ellipsometric (SE) data (ψ and Δ) acquired in the wavelength range 400–1700 nm, were analyzed using a multilayer approach. The extracted refractive indices were found to follow a Cauchy-type dispersion. Upon SiN treatment, there is a blueshift and a decrease in the refractive index. At 600 nm, the GaN refractive index decreases from 2.395 to 2.374. The SE refractive indices measurements agree with the spectroscopic reflectometry (SR) results.

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Section: Resultssupporting

confidence: 84%

A study of the effects of SiN treatment on the GaN refractive index

Chalabi,

Laifi,

Bchetnia

et al. 2024

Preprint

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“…Compared with Sample B, Sample A increases the J SC of the SCs from 1.79 mA cm −2 to 5.54 mA cm −2 and the PCE from 4.29% to 4.37% due to the tunneling effect model. However, due to significant defects in the epitaxial materials of the SLs structure during the growth process, these dislocations serve as non-radiative recombination centers in the device, reducing the device's R sh and further increasing leakage current, ultimately leading to a decrease in V OC of the SCs with SLs structure compared to the SCs with MQWs structure from 2.65 V to 1.22 V. [27][28][29] This is the same trend as the experimental values. The exact values can be seen in the inset of Fig.…”

supporting

confidence: 76%

Enhancement of Short-Circuit Current Density in Superlattice-Based InGaN/GaN Solar Cells

Shan,

Song,

et al. 2023

ECS J. Solid State Sci. Technol.

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The mechanism of short-circuit current density (Jsc) enhancement in InGaN/GaN superlattices(SLs)-structured solar cells (SCs) was investigated theoretically and experimentally, and compared with conventional InGaN/GaN multiple quantum wells SCs. Due to the ultrathin structure of the X-ray diffraction SLs, a tunneling model was introduced in Silvaco software. The simulation results showed that the trend of the simulation results is consistent with the experimental values. Due to the contribution of the tunneling effect, the Jsc of SCs with SLs structure was greatly improved, but the open circuit voltage was also reduced due to defects in the growth process of epitaxial wafers with SLs structure. These observations suggest that tunneling effects increase the Jsc of the SCs, thus improving the photovoltaic conversion efficiency of SCs. This study provides evidence for the fabrication of highly efficient InGaN SCs.

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“…The dislocation densities are similar to those of GaN films grown on LGS by MBE, 10 indicating that the GaN films with similar quality are prepared using a more economical method. However, the dislocation densities are more than 1 order of magnitude higher than the GaN films grown on the sapphire substrate by several improved techniques in recent years, 29,30 thus the growth conditions should be further optimized in order to raise the quality of films. So far, no research has investigated the type of the TDs of GaN films grown on LGS-type crystals; Figure 7 shows the cross-sectional TEM images of GaN films in this work.…”

Section: Structure Characterization Of Gan Films On Cnasmentioning

confidence: 99%

Growth of Single-Crystalline GaN Films on Ga-Free Langasite-Type Crystals by Metal–Organic Chemical Vapor Deposition

Wang,

Xu,

Wang

et al. 2023

Crystal Growth & Design

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Langasite (La 3 Ga 5 SiO 14 , LGS) family crystals are known for their piezoelectric properties, which make them widely applicable in surface acoustic wave (SAW) devices. The group-III metal nitrides formed on LGS substrates are found to enable significant extension of SAW devices to higher-frequency ranges. However, the Ga element in LGS crystals is observed to volatilize in H 2 at high temperatures, forming Ga droplets and degrading the film quality. This study reports the growth of GaN films on the Ga-free LGS-type crystal Ca 3 NbAl 3 Si 2 O 14 (CNAS) by metal−organic chemical vapor deposition (MOCVD), and the CNAS is stable in MOCVD. The as-grown GaN films are continuous and smooth with a roughness of 0.369 nm. The epitaxial relationship between GaN and CNAS is GaN(0001)//CNAS(0001) and GaN(10−12)//CNAS(21−32). The mixed dislocations are found to be dominant type of dislocations of the GaN films on CNAS. The GaN films also exhibit good optical properties and a compressive stress of 0.17 GPa. Thus, the results indicate that the Ga-free LGS-type crystals have great potential for applications in the epitaxial growth of GaN materials.

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Dislocation density control of GaN epitaxial film and its photodetector

Cited by 11 publications

References 34 publications

A study of the effects of SiN treatment on the GaN refractive index

A study of the effects of SiN treatment on the GaN refractive index

Enhancement of Short-Circuit Current Density in Superlattice-Based InGaN/GaN Solar Cells

Growth of Single-Crystalline GaN Films on Ga-Free Langasite-Type Crystals by Metal–Organic Chemical Vapor Deposition

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