Lateral current spreading in GaN-based light-emitting diodes utilizing tunnel contact junctions

Jeon, Sohee; Song, Young-Ho; Jang, Ho-Jin; Yang, Gye Mo; Hwang, Soon Won; Son, Seung Bae

doi:10.1063/1.1374483

Cited by 170 publications

(99 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The n-GaN layer in device A has a lower spreading resistance than p-GaN in device B, which increases the emission area in n-ZnO/p-GaN heterostructure diodes. 30 Therefore, we attribute the enhanced light output power of device A to the improved current spreading.…”

mentioning

confidence: 99%

n-ZnO/p-GaN heterojunction light-emitting diodes featuring a buried polarization-induced tunneling junction

Zhang

Liu

et al. 2016

AIP Advances

View full text Add to dashboard Cite

n-ZnO/p-GaN heterojunction light-emitting diodes with a p-GaN/Al0.1Ga0.9N/n+-GaN polarization-induced tunneling junction (PITJ) were fabricated by metal-organic chemical vapor deposition. An intense and sharp ultraviolet emission centered at ∼396 nm was observed under forward bias. Compared with the n-ZnO/p-GaN reference diode without PITJ, the light intensity of the proposed diode is increased by ∼1.4-folds due to the improved current spreading. More importantly, the studied diode operates continuously for eight hours with the decay of only ∼3.5% under 20 mA, suggesting a remarkable operating stability. The results demonstrate the feasibility of using PITJ as hole injection layer for high-performance ZnO-based light-emitting devices.

show abstract

mentioning

confidence: 99%

n-ZnO/p-GaN heterojunction light-emitting diodes featuring a buried polarization-induced tunneling junction

Zhang

Liu

et al. 2016

AIP Advances

View full text Add to dashboard Cite

show abstract

“…2(a)). [16][17][18][19][20][21][22] Due to the polarization discontinuity, sheet charges with density over 10 13 cm -2 are induced at the AlGaN/InGaN heterointerfaces and this reduces the tunneling barrier to less than 3 nm ( Fig. 2(b)), leading to much higher tunneling probability compared to the homojunction tunnel junction.…”

mentioning

confidence: 99%

Design and demonstration of ultra-wide bandgap AlGaN tunnel junctions

Zhang

Krishnamoorthy

Akyol

et al. 2016

Applied Physics Letters

View full text Add to dashboard Cite

Ultra violet light emitting diodes (UV LEDs) face critical limitations in both the injection efficiency and light extraction efficiency due to the resistive and absorbing p-type contact layers. In this work, we investigate the design and application of polarization engineered tunnel junctions for ultra-wide bandgap AlGaN (Al mole fraction > 50%) materials towards highly efficient UV LEDs. We demonstrate that polarization-induced 3D charge is beneficial in reducing tunneling barriers especially for high composition AlGaN tunnel junctions. The design of graded tunnel junction structures could lead to low tunneling resistance below 10 -3 Ω cm 2 and low voltage consumption below 1 V (at 1 kA/cm 2 ) for high composition AlGaN tunnel junctions. Experimental demonstration of 292 nm emission was achieved through non-equilibrium hole injection into wide bandgap materials with bandgap energy larger than 4.7 eV, and detailed modeling of tunnel junctions shows that they can be engineered to have low resistance, and can enable efficient emitters in the UV-C wavelength range.a) Authors to whom correspondence should be addressed. Electronic mail: zhang.3789@osu.edu, rajan@ece.osu.edu 2The large range of direct bandgaps in the III-Nitride system makes these semiconductors uniquely suitable for achieving ultra violet emission over a wide wavelength range down to 210 nm. III-Nitride ultra-violet light emitting diodes (UV LEDs) have a large variety of applications including water purification and air disinfection, and they provide distinct advantages over traditional gas-based lamps. We propose an approach to realize highly efficient hole injection based on interband tunneling. In this approach, a transparent n-type AlGaN layer is connected to the p-AlGaN layer using an interband tunnel junction ( Fig. 1(b)). Non-equilibrium tunneling injection of holes overcomes limits imposed by thermal ionization of deep acceptors. 9,10 At the same time, it leads to efficient light extraction since it eliminates absorbing p-type top contact layers. 11Making efficient interband p-n tunnel junctions is challenging for ultra-wide bandgap AlGaN materials due to the large band gap, wide depletion barrier, and doping limitations. In this work, we show that nanoscale heterostructure and polarization engineering of tunnel junctions can enable highly efficient tunneling even for ultra-wide bandgap materials where ordinary dopant-based homojunctions would have very low tunneling current density. In this letter, we discuss the design of AlGaN tunnel junctions over the entire Al composition range. We then experimentally demonstrate highly efficient tunnel junctions for AlGaN with Al composition greater than 50%. was used for tunneling probability calculation, and tunneling current was calculated by considering all possible contributions by carriers with different energies. Bandtail states and bandgap narrowing effect due to heavy impurity doping are not included in the simulations, though they could lead to increase in the tunneling probability. ...

show abstract

“…Cp 2 Mg flow rate is likely to modulate the energy position of the current channel. This model appears to be more plausible also in explaining the p+/n+GaN tunnel junction [8]. In this case, tunneling between conduction band and accepter impurity band is predominant at the junctions.…”

Section: Resultsmentioning

confidence: 88%

Impurity band in magnesium‐doped GaN layers grown by metalorganic chemical vapor deposition

Kang

Cheong

Lee

et al. 2004

Physica Status Solidi (b)

View full text Add to dashboard Cite

InGaN/GaN quantum well light emitting diodes (LEDs) were grown with p-GaN layers of varied Mg impurity content. As the concentration of Mg impurity increases, the hole concentration increases up to a critical Mg impurity density and then decreases with further increase of the impurity. In this work, it is proposed that the accepters form the impurity band and that the band behavior with Mg content variation is attributed to the properties of the p-GaN layer and the p-layer effect on the I -V characteristics of LED.

show abstract

Lateral current spreading in GaN-based light-emitting diodes utilizing tunnel contact junctions

Cited by 170 publications

References 15 publications

n-ZnO/p-GaN heterojunction light-emitting diodes featuring a buried polarization-induced tunneling junction

n-ZnO/p-GaN heterojunction light-emitting diodes featuring a buried polarization-induced tunneling junction

Design and demonstration of ultra-wide bandgap AlGaN tunnel junctions

Impurity band in magnesium‐doped GaN layers grown by metalorganic chemical vapor deposition

Contact Info

Product

Resources

About