High quality AlN with uniform in-plane strain on nano-patterned AlN templates achieved by preset strain modulation

Abstract High-quality AlN with uniform in-plane strain has been attempted with preset strain modulation on nano-patterned AlN templates (NPATs). It is found that this strain preset frame can effectively improve both the tilt and twist features of AlN on NPATs, further greatly decreasing threading dislocation density. More importantly, the AlN epilayer after completing coalescence can maintain the in-plane uniform compressive strain. Adopting AlN templates achieved in this scheme, the chip-on-wafer light output power (LOP) of AlGaN light-emitting diode (LED) reaches 10.2 mW at 100 mA with single emission peak at 280 nm, which increases by 22.3% than the LOP of LED device without adopting this strain preset frame.

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Strain Modulation of Selectively and/or Globally Grown Ge Layers

Nanomaterials ◽

10.3390/nano11061421 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1421

Author(s):

Yong Du ◽

Guilei Wang ◽

Yuanhao Miao ◽

Buqing Xu ◽

Ben Li ◽

...

Keyword(s):

Growth Parameters ◽

Compressive Strain ◽

Hole Mobility ◽

Bandgap Energy ◽

Threading Dislocation ◽

High Quality ◽

Threading Dislocation Density ◽

Novel Method ◽

Pl Intensity ◽

Strain Modulation

This article presents a novel method to grow a high-quality compressive-strain Ge epilayer on Si using the selective epitaxial growth (SEG) applying the RPCVD technique. The procedures are composed of a global growth of Ge layer on Si followed by a planarization using CMP as initial process steps. The growth parameters of the Ge layer were carefully optimized and after cycle-annealing treatments, the threading dislocation density (TDD) was reduced to 3 × 107 cm−2. As a result of this process, a tensile strain of 0.25% was induced, whereas the RMS value was as low as 0.81 nm. Later, these substrates were covered by an oxide layer and patterned to create trenches for selective epitaxy growth (SEG) of the Ge layer. In these structures, a type of compressive strain was formed in the SEG Ge top layer. The strain amount was −0.34%; meanwhile, the TDD and RMS surface roughness were 2 × 106 cm−2 and 0.68 nm, respectively. HRXRD and TEM results also verified the existence of compressive strain in selectively grown Ge layer. In contrast to the tensile strained Ge layer (globally grown), enhanced PL intensity by a factor of more than 2 is partially due to the improved material quality. The significantly high PL intensity is attributed to the improved crystalline quality of the selectively grown Ge layer. The change in direct bandgap energy of PL was observed, owing to the compressive strain introduced. Hall measurement shows that a selectively grown Ge layer possesses room temperature hole mobility up to 375 cm2/Vs, which is approximately 3 times larger than that of the Ge (132 cm2/Vs). Our work offers fundamental guidance for the growth of high-quality and compressive strain Ge epilayer on Si for future Ge-based optoelectronics integration applications.

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Details of the improvement of crystalline quality of a-plane GaN using one-step lateral growth

MRS Proceedings ◽

10.1557/proc-0955-i04-02 ◽

2006 ◽

Vol 955 ◽

Author(s):

Daisuke Iida ◽

Tetsuya Nagai ◽

Takeshi Kawashima ◽

Aya Miura ◽

Yoshizane Okadome ◽

...

Keyword(s):

Defect Density ◽

Light Output ◽

Epitaxial Lateral Overgrowth ◽

Root Mean Square Roughness ◽

Threading Dislocation ◽

Light Emitting ◽

Lateral Overgrowth ◽

Green Led ◽

Threading Dislocation Density ◽

One Step

ABSTRACTLow defect density a-plane GaN films were successfully grown by sidewall epitaxial lateral overgrowth (SELO) technique. Control of V/III ratio during the growth of GaN by metalorganic vapor phase epitaxy (MOVPE) was found to be very important to achieve a complete overgrowth on the SiO2 mask regions and atomically flat surface. The threading dislocation and stacking fault densities in the overgrown regions were lower than 106 cm−2 and 103 cm−1, respectively. The root mean square roughness was 0.09 nm. We also fabricated and characterized a-plane-GaN-based-light-emitting diodes (LEDs) using SELO technique. The light output power of the blue-green LED steeply increased with the decrease of threading dislocation density from 1010 cm−2 to 108 cm−2 and tended to saturate at lower dislocation densities.

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227 nm AlGaN Light-Emitting Diode with 0.15 mW Output Power Realized using a Thin Quantum Well and AlN Buffer with Reduced Threading Dislocation Density

Applied Physics Express ◽

10.1143/apex.1.051101 ◽

2008 ◽

Vol 1 ◽

pp. 051101 ◽

Cited By ~ 79

Author(s):

Hideki Hirayama ◽

Norimichi Noguchi ◽

Tohru Yatabe ◽

Norihiko Kamata

Keyword(s):

Dislocation Density ◽

Quantum Well ◽

Output Power ◽

Light Emitting Diode ◽

Threading Dislocation ◽

Light Emitting ◽

Threading Dislocation Density ◽

Aln Buffer

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Analysis of EL Emitted by LEDs on Si Substrates Containing GeSn/Ge Multi Quantum Wells as Active Layers

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.242.361 ◽

2015 ◽

Vol 242 ◽

pp. 361-367 ◽

Cited By ~ 1

Author(s):

Bernhard Schwartz ◽

Philipp Saring ◽

Tzanimir Arguirov ◽

Michael Oehme ◽

Konrad Kostecki ◽

...

Keyword(s):

Quantum Wells ◽

Heavy Hole ◽

Compressive Strain ◽

Threading Dislocation ◽

Light Emitting ◽

Si Substrates ◽

Active Layers ◽

Hole Band ◽

Threading Dislocation Density ◽

Multi Quantum Well

We analyzed multi quantum well light emitting diodes, consisting of ten alternating GeSn/Ge-layers, were grown by molecular beam epitaxy on Si. The Ge barriers were 10 nm thick and the GeSn wells were grown with 7% Sn and thicknesses between 6 and 12 nm. Despite the high threading dislocation density of 109to 1010cm−2the electroluminescence spectra measured at 300 and 80 K yield a broad and intensive luminescence band. Deconvolution revealed three major lines produced by the GeSn wells that can be interpreted in terms of quantum confinement. Biaxial compressive strain causes a splitting of light and heavy holes in the GeSn wells. We interpret the three lines to represent two direct lines, formed by transitions with the light and heavy hole band, respectively, andan indirect line.

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High Efficiency Uv Emitter Using High Quality GaN/AlxGa1−xN Multi-Quantum Well Active Layer

MRS Proceedings ◽

10.1557/proc-639-g12.3 ◽

2000 ◽

Vol 639 ◽

Author(s):

M. Iwaya ◽

S. Terao ◽

T. Ukai ◽

R. Nakamura ◽

S. Kamiyama ◽

...

Keyword(s):

Dislocation Density ◽

Quantum Wells ◽

High Efficiency ◽

Light Emitting Diode ◽

Threading Dislocation ◽

Light Emitting ◽

Si Doping ◽

Threading Dislocation Density ◽

Pl Intensity ◽

Multi Quantum Well

ABSTRACTWe investigated temperature dependence of the photoluminescence (PL) efficiency of GaN/Al0.08Ga0.92N multi-quantum wells (MQWs) with variations of Si-doping condition and threading dislocation density. Si-doping in the GaN/Al0.08Ga0.92N MQWs, especially in the barrier layer improves the PL efficiency. In addition, reduction of threading dislocation density also improves the PL intensity. The PL intensity of the GaN/Al0.08Ga0.92N MQW is drastically increased at least by a factor of 40, by a combination of the Si-doping and reduction of threading dislocation density. We fabricated a light emitting diode (LED) emitting at 357 nm using such a GaN/Al0.08Ga0.92N MQWs. Electro-luminescence intensity from the region with threading dislocation density of less than 108 cm−2 was much larger than that from the region with threading dislocation density of 6×109 cm−2.

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Red Light-Emitting Diodes with All-Inorganic CsPbI3/TOPO Composite Nanowires Color Conversion Films

Nanoscale Research Letters ◽

10.1186/s11671-020-03430-w ◽

2020 ◽

Vol 15 (1) ◽

Author(s):

Lung-Chien Chen ◽

Yi-Tsung Chang ◽

Ching-Ho Tien ◽

Yu-Chun Yeh ◽

Zong-Liang Tseng ◽

...

Keyword(s):

Quantum Dots ◽

Light Emitting Diode ◽

Red Light ◽

Trioctylphosphine Oxide ◽

Optical And Electrical Properties ◽

Colloidal Solutions ◽

High Quality ◽

Light Emitting ◽

Hot Injection ◽

Color Conversion

AbstractThis work presents a method for obtaining a color-converted red light source through a combination of a blue GaN light-emitting diode and a red fluorescent color conversion film of a perovskite CsPbI3/TOPO composite. High-quality CsPbI3 quantum dots (QDs) were prepared using the hot-injection method. The colloidal QD solutions were mixed with different ratios of trioctylphosphine oxide (TOPO) to form nanowires. The color conversion films prepared by the mixed ultraviolet resin and colloidal solutions were coated on blue LEDs. The optical and electrical properties of the devices were measured and analyzed at an injection current of 50 mA; it was observed that the strongest red light intensity was 93.1 cd/m2 and the external quantum efficiency was 5.7% at a wavelength of approximately 708 nm when CsPbI3/TOPO was 1:0.35.

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A 3 W High-Voltage Single-Chip Green Light-Emitting Diode with Multiple-Cells Network

Journal of Nanomaterials ◽

10.1155/2015/248191 ◽

2015 ◽

Vol 2015 ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

W. Wang ◽

Y. Cai ◽

Y. B. Zhang ◽

H. J. Huang ◽

W. Huang ◽

...

Keyword(s):

High Voltage ◽

Light Emitting Diode ◽

Light Output ◽

Green Light ◽

Current Crowding ◽

Single Chip ◽

Light Output Power ◽

Large Area ◽

Light Emitting ◽

Multiple Cells

A parallel and series network structure was introduced into the design of the high-voltage single-chip (HV-SC) light-emitting diode to inhibit the effect of current crowding and to improve the yield. Using such a design, a6.6×5 mm2large area LED chip of 24 parallel stages was demonstrated with 3 W light output power (LOP) at the current of 500 mA. The forward voltage was measured to be 83 V with the same current injection, corresponding to 3.5 V for a single stage. The LED chip’s average thermal resistance was identified to be 0.28 K/W by using infrared thermography analysis.

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