Influence of growth rate in the early stage of high temperature GaN layer growth on quality of GaN films

Li, Shuti; Su, J.; Fan, Guanghan; Zhang, Yong; Zheng, Shuwen; Sun, Hong‐Bo; Cao, Jianxing

doi:10.1016/j.jcrysgro.2008.05.055

Cited by 14 publications

(9 citation statements)

References 15 publications

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“…And then, by directly adjusting the SiH 4 flow rate, unintentionally doped and three Si doped GaN microwire arrays were synthesized, whose carrier concentrations were respectively 1.0 × 10 17 (undoped), 3.0 × 10 17 , 1.0 × 10 18 , 5.0 × 10 18 cm –3 . The corresponding carrier concentrations were at a similar level to the published articles. − The growth procedure could be described in detail previously . The representative as-grown GaN microwire array on Si is schematically shown in Figure a.…”

Section: Methodsmentioning

confidence: 82%

Optimization of All Figure-of-Merits in Well-Aligned GaN Microwire Array Based Schottky UV Photodetectors by Si Doping

Wang

Luo

et al. 2019

ACS Photonics

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GaN nano/microwires, due to their large surface-tovolume ratio and the reduced dimensionality, have been widely used in high-performance ultraviolet (UV) photodetectors (PDs). However, there has been a fundamental trade-off between the photocurrent gain and the speeds of PDs, which have limited their practical applications. In this work, highly ordered GaN microwire array based Schottky UV PDs have been fabricated, and optimizing Si doping concentrations can entirely improve the performances of the devices. The results show that output photocurrent increases monotonously as increasing doping concentration, while the dark current experiences a decrease followed by an increase, resulting in an optimized value under a certain doping concentration. At doping concentration of 1 × 10 18 cm −3 with 2.2 mW cm −2 illuminating intensity, the sensitivity, responsivity, and detectivity of the devices are greatly enhanced by 1.84 × 10 4 %, 163%, and 2103%, respectively. Meanwhile, the time-dependent response in Si-doped device possesses fast response time (τ on < 10 ms and τ off < 10 ms) at this optimum concentration, compared with that of undoped one (τ on = 70 ms and τ off = 90 ms). The effective advances in the devices are attributed to the increased Schottky barrier height by Si doping and the intensive oxygen molecules adsorption and desorption processes in microwire surface. This study offers a design guideline for the optimum doping concentration for obtaining high performances in microwire-based PDs.

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Section: Methodsmentioning

confidence: 82%

Optimization of All Figure-of-Merits in Well-Aligned GaN Microwire Array Based Schottky UV Photodetectors by Si Doping

Wang

Luo

et al. 2019

ACS Photonics

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“…On the surface, there are also some dark spots which Step terminations on a single crystal surface correspond to the intersection of a threading dislocation with the free surface. 23 The terminated steps and roughness of 25 nm sample are less than those of 15 nm sample. For 45 nm sample, some cracks and hillocks can be observed and the steps are not at.…”

Section: Resultsmentioning

confidence: 94%

The evolution of a GaN/sapphire interface with different nucleation layer thickness during two-step growth and its influence on the bulk GaN crystal quality

et al. 2015

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The role of the nucleation layer thickness on the GaN crystal quality grown by metal organic chemical vapor deposition is explored. The surface morphologies of a low-temperature GaN nucleation layer (NL) investigated by Atomic Force Microscopy shows the nuclei grain size increases with increasing thickness.After annealing, island-like morphologies of the low-temperature GaN NL are obtained. Increasing the NL thickness is beneficial for obtaining larger island size, however, the uniformity of the island size is deteriorated. The high-resolution X-ray diffraction analysis reveals that bulk GaN crystal properties are closely connected with NL thickness, which can be well explained by the dislocation generation and propagation process in the GaN films. All the obtained results indicate that the NL thickness effectively controls the size and density of the islands and thus determines the crystal properties of GaN films. Fig. 6 The AFM images (3 Â 3 mm) (left) of bulk GaN with 15, 25 and 45 nm-NL thickness and the line profiles of the surface (right).Fig. 7 The AFM images (5 Â 5 mm) of bulk GaN after etching with 15, 25 and 45 nm-NL thickness.This journal is

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“…[5] and Chen J. [6] studied respectively the optimum value of pressure in reactor, and found lower pressure is propitious to improve crystal photoelectric properties; Li S. T. [7] and Paskova T. [8] studied respectively the effect of growth rate on HVPE-GaN; GU S. L. [9] considered it is helpful to obtain smooth surface that an amount of H 2 is added into N 2 , which causes the decline of NH 3 reaction and the motility of N atom on growth layer surface; Richter E. [10] optimized the parameters of reactor and growth process. In order to study the effect of different carrier gases on thick HVPE-GaN films and optimize the parameter of carrier gas, difference of crystal growth modes in H 2 and N 2 are analyzed from growth mechanism point of view by experiments.…”

Section: Introductionmentioning

confidence: 99%

Effect of Carrier Gas on Crystal Quality of Thick HVPE-GaN Films

Wang¹,

Xu²,

Yang³

et al. 2010

2010 Symposium on Photonics and Optoelectronics

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The effect of carrier gas on thick GaN film grown by hydride vapor phase epitaxy on (0001) sapphire substrate has been studied by double crystal X-ray diffraction (DCXRD), polarizing microscope and field emission scanning electron microscope (FE-SEM). H 2 , as carrier, is propitious to two-dimension growth pattern of GaN film but causes production of more defects and impurities. N 2 , as carrier, weakens pre-reaction and reduces content of defects and impurities, however, growth interface of GaN forms easily crystallographic facets but not epitaxial (0002) plane, which leads to appearing of protuberances. It may gain high crystal quality that first H 2 and then N 2 is adopted as carrier gas.

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Influence of growth rate in the early stage of high temperature GaN layer growth on quality of GaN films

Cited by 14 publications

References 15 publications

Optimization of All Figure-of-Merits in Well-Aligned GaN Microwire Array Based Schottky UV Photodetectors by Si Doping

Optimization of All Figure-of-Merits in Well-Aligned GaN Microwire Array Based Schottky UV Photodetectors by Si Doping

The evolution of a GaN/sapphire interface with different nucleation layer thickness during two-step growth and its influence on the bulk GaN crystal quality

Effect of Carrier Gas on Crystal Quality of Thick HVPE-GaN Films

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