ANN NIRT GOALI Nano-Engineering Efficient Optoelectronic Devices NSF Grant ECS – 0609416 PIs: S. Nikishin, J. Berg, A. Bernussi, M. Holtz, H. Temkin Nano Tech Center, Texas Tech University, Lubbock TX-79409. (a). Basic LED Design. Starting surface (GaN). p -type AlGaN.
Nano-Engineering Efficient Optoelectronic Devices
NSF Grant ECS – 0609416
PIs: S. Nikishin, J. Berg, A. Bernussi, M. Holtz, H. Temkin
Nano Tech Center, Texas Tech University, Lubbock TX-79409
Basic LED Design
Starting surface (GaN)
AlN/AlGaN active region
AlGaN or AlN template
Nanophotonic Texturing Experiments for Enhancing Light Extraction – GaN
Active Region Nano-Engineering
The room temperature CL intensity
Of QWs versus NH3 flux. Insets are
depiction of quantum structure
formation and TEM cross-section of
Ammonia flux, growth mode, and corresponding RHEED
images (insets a, b, c, and d) versus growth time of well
material. Sample #1 (21 s growth time) – onset of
3D growth mode; #2 (26 s growth time) – at least 3/5 of
well is grown in 3D mode; sample #3 (32 s growth time);
sample #4 (42 s growth time) – onset of 3D →2D transition.
CL and PL data versus growth time of well material. PL excitation energy density is 0.72 µJ/cm2. (a) peak position, (b) intensity, and (c) 1/e decay time. The dashed horizontal line is the bandgap of the bulk Al0.4Ga0.6N material. Filled circle is CL of 2D grown well material.
0 2.5 5.0 7.5 10.0
Substrate design for improved epitaxy.
(GOALI partner – TDI Inc.)
Plan-view 10 X 10 μm2 AFM scan of HVPE grown 6.4 μm thick AlN/sapphire template. The surface RMS roughness is ~ 3 nm. Step-flow growth mode
X-ray reciprocal space map (RSM) for (0002) reflection of AlN template.
FWHMω-scan=100" & FWHM2Θ-ω=110".
Inset: TEM cross-section of AlN/sapphire interface.
This project provides nine students at the BS, MS, and PhD levels with a fully integrated multidisciplinary setting for research and training. Of the students involved in this work, five are female, and one of those was African-American. Three senior researchers are involved in research under this program.
Technologies and Devices International, Inc.; Army Research Laboratory; Veeco Instruments, Inc.; Soft-Impact, Ltd.; The Fox Group, Inc.
Select publications under this grant
“Transmission properties of nanoscale aperture arrays in metallic masks on optical fibers,” J. Appl. Phys. 101, 014303 (2007).
“Selective area growth of GaN nano islands by metal organic chemical vapor deposition: experiments and computer simulations,” Proc. Mat. Res. Soc. Symp., 955, 0955-I07 (2007).
“Enhanced luminescence from AlxGa1-xN/ AlyGa1-yN quantum wells grown by gas source molecular beam epitaxy with ammonia,” Proc. SPIE Photonics Conf., 6473, 647306 (2007).
“X-ray diffraction study of AlN/AlGaN short period superlattices”, J. Appl. Phys., JR07-3866R (2007).
“Deep UV light emitting diodes and solar blind photodetectors grown by gas source molecular beam epitaxy”, J. Mater. Sci: Mater Electron, DOI: 10.1007/s10854-007-9405-3 (2007).
“Luminescence properties of AlxGa1-xN (0.4<x<0.5)/AlyGa1-yN (0.6<y≤1) quantum structures grown by gas source molecular beam epitaxy”, physica status solidi c (2007).
“Influence of photonic nanotexture on the optical properties of GaN”, Appl. Phys. Lett. 91, 103115 (2007).
50-mm AlN free standing wafer fabricated at TDI Inc. HVPE growth of thick AlN layer on SiC substrates and subsequent removal of the SiC substrate by RIE. (Courtesy of TDI Inc.)