Enhancement of deep acceptor activation in semiconductors by superlattice doping

Schubert, E. Fred; Grieshaber, W.; Goepfert, I. D.

doi:10.1063/1.117206

Cited by 137 publications

(86 citation statements)

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“…This provides a periodic oscillation in the valence band edge, allowing ionisation of acceptors in the wide bandgap AlGaN layers to provide hole accumulation in the adjacent GaN layers, leading to an overall increase in hole concentration [45]. The principle is illustrated in .…”

Section: P-type Dopingmentioning

confidence: 99%

Solid-State Lighting Based on Light Emitting Diode Technology

Zhu

Humphreys

2016

Optics in Our Time

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Section: P-type Dopingmentioning

confidence: 99%

Solid-State Lighting Based on Light Emitting Diode Technology

Zhu

Humphreys

2016

Optics in Our Time

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“…They argue that, as the electrically active acceptor concentration increases, the isolated deep acceptor levels begin to interact and split into an impurity band, which is closer to the valence band thus lowering the effective activation energy. Peter and Schubert 24,25 demonstrated another strategy and found that by polarization induced modulation of the valence band edge in a superlattice, the low doping efficiency could be partially overcome. Simon and Jena 26 also suggested that a 3D hole gas could be produced using the builtin electronic polarization in nitrides.…”

Section: Present Solution For P Doping Difficultiesmentioning

confidence: 99%

“…edge produced by a superlattice structure, such as AlxGa1-xN/GaN, can also modify the characteristics and energy position of the VBM. 31,32 Based on this consideration, a novel strategy for efficient p-type doping is proposed to overcome the fundamental problem of high activation energy by inducing impurity resonant states in an Mg doped AlxGa1-xN/GaN superlattice structure. As schematically shown in Fig.…”

Section: New Strategy Based On Band-engineeringmentioning

confidence: 99%

“…In addition, as proposed by previous reports, the polarization effect also enhances the ionization of the deep acceptors and leads to the accumulation of carriers as a hole sheet, which further increase the effective hole concentration in the host materials. 31,32,39 To test these proposed concepts, the impact of impurity resonant states on the ionization energy of Mg acceptors is analyzed through both theoretical and experimental methods.…”

Section: New Strategy Based On Band-engineeringmentioning

confidence: 99%

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Comprehensive Theoretical and Experimental Studies on Iii-Nitrides, Doping, Nano-Structures and Leds

Li¹,

Liu²,

Yi³

et al. 2017

III-Nitride Materials, Devices and Nano-Structures

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Even though III-Nitrides have demonstrated their ample application in solid-state light, display, laser, detector and high-power RF/switching device, many other new breakthroughs on fundamental physics and fabrication techniques are still highly desired to lead to their next expansion of the research and application field in the near future. In this chapter, the general properties of III-nitrides as well as their ternary and quaternary were briefly reviewed. Specifically, we mainly focused on the underlying physics of p doping challenge, nitrides nano-structures and their application on LEDs. We presented an overview of some main results and progress in highly effective p doping for nitrides. Some promising strategies to address the issue of p doping challenge were also introduced. Furthermore, we describe the prevailing GaN nanowire fabrication methods including wet etching and selective area growth and their application in novel LED structures.

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“…37,[134][135][136][137] Because of the SL structures, low-resistance ohmic contacts to pGaN/Al x Ga 1-x N was shown to form, producing specific contact resistivity ∼10 …”

Section: 99mentioning

confidence: 99%

Review—Group III-Nitride-Based Ultraviolet Light-Emitting Diodes: Ways of Increasing External Quantum Efficiency

Park

Kim

Cho

et al. 2017

ECS J. Solid State Sci. Technol.

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There is a rapidly growing demand for highly efficient ultraviolet (UV) light sources for a wide variety of applications. In particular, state-of-the-art AlGaN deep UV light-emitting diodes (DUV LEDs) exhibit inadequately low external quantum efficiencies (EQEs). The low efficiencies are attributed to the inherent material properties of high-Al-content AlGaN including strained epitaxial layers, low carrier concentrations, and strong transverse magnetic (TM)-polarized light emission. Extensive efforts have been made to tackle these challenging issues and technological developments have been achieved and enabled the fabrication of reasonable EQE LEDs. In this review, recent advances in the growth of high-quality AlGaN epitaxial layers, transparent and reflective ohmic contacts, and light extraction for AlGaN-based UV LEDs are reviewed. Al x Ga 1-x N-based ultraviolet light-emitting diodes (UV LEDs) are of technological importance because of their applications in numerous areas such as water purification, biological analysis, sensing, epoxy curing, high-density optical storage, white light illumination, UV adhesives, 3-dimensional (3D) printer and UV-coating.1,2 These applications are made possible because of their wide bandgap energy range in the UV spectrum, which spans from 6.2 eV (AlN) to 3.4 eV (GaN), namely, from UV-A (320-400 nm), UV-B (290-320 nm) to UV-C (200-290 nm).3-7 The external quantum efficiency (EQE) of Al x Ga 1-x N-based UV LEDs decreases rapidly as the molar fraction (x) of Al increases, namely, as the wavelength decreases, as illustrated in Figure 1. 8 Thus, a great deal of effort has been made in order to improve the EQE of UV LEDs. The effort notwithstanding, however, the EQE of AlGaN-based UV LEDs is still insufficiently low. The typical EQE of UV LEDs, specifically in the UV-C spectral range (100-280 nm), is less than 5% and decreases down to 10 -6 % for 210-nm AlN-based UV LEDs. 4 These low EQEs are associated with the intrinsic material properties of Al x Ga 1-x N.1,2 Figure 2 exhibits a schematic diagram of a typical AlGaN UV LED structure grown on a sapphire substrate. The structure consists of a Si-doped n-type AlGaN, an Al x Ga 1-x N/Al y Ga 1-y N multiple-quantum well (MQW) active region, an AlGaN-based electron-blocking layer (EBL), a Mg-doped p-type AlGaN, and a Mg-doped p-type GaN. Almost every layer in the structure poses different technical issues, which limit the efficiency of UV LEDs, as shown in Figure 2. First, increasing the Al content generally results in a poor crystallinity of AlGaN epilayers, causing a poor internal quantum efficiency (IQE). Second, both n-type and ptype doping efficiencies of AlGaN are difficult to increase because the ionization energies of acceptor (Mg) and donor (Si) dopants largely increase with increasing Al content. The low doping efficiency causes several technological problems: (i) a poor electrical efficiency (EE) attributable to high-resistance contacts on resistive n-type and p-type AlGaN; (ii) current crowding causing non-uniform current in...

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Enhancement of deep acceptor activation in semiconductors by superlattice doping

Abstract: Public reporting burden for this collection of information is estimated

Cited by 137 publications

References 1 publication

Solid-State Lighting Based on Light Emitting Diode Technology

Solid-State Lighting Based on Light Emitting Diode Technology

Comprehensive Theoretical and Experimental Studies on Iii-Nitrides, Doping, Nano-Structures and Leds

Review—Group III-Nitride-Based Ultraviolet Light-Emitting Diodes: Ways of Increasing External Quantum Efficiency

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