Nuchnipa Nuntawong

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We demonstrate the ability to form either coupled or isolated patterned quantum dot ͑PQD͒ ensembles on nanopatterned GaAs pyramidal buffers. The coupled PQD " clusters " consist of close-spaced PQDs with inter-QD spacing of 5 nm. The isolated PQD " pairs " are comprised of two PQDs well separated by 110 nm. The photoluminescence behavior, measured in(More)
We report optical, electrical, and spectral response characteristics of three-stack InAs/ GaAs quantum dot solar cells with and without GaP strain compensation ͑SC͒ layers. The short circuit current density, open circuit voltage, and external quantum efficiency of these cells under air mass 1.5 G at 290 mW/ cm 2 illumination are presented and compared with(More)
A GaSb quantum-well (QW) laser diode grown monolithically on a 5 miscut Si (001) substrate is presented. The III-Sb epi-structure is grown monolithically on the miscut Si substrate via a thin (50 nm) AlSb nucleation layer. The 13% lattice mismatch between AlSb and Si is accommodated by a self-assembled, 2D array of interfacial misfit dislocations (IMF). The(More)
Single InAs quantum dots, site-selectively grown by a patterning and regrowth technique, were probed using high-resolution low-temperature microphotoluminescence spectroscopy. Systematic measurements on many individual dots show a statistical distribution of homogeneous linewidths with a peak value of ϳ120 ␮eV, exceeding that of unpatterned dots but(More)
The authors report the effect of localized strain in stacked quantum dots ͑QDs͒ with strain-compensation ͑SC͒ layers by evaluating the vertical coupling probability of QD formation between stacks measured as a function of spacer thickness. The localized strain field induced at each QD can be partially suppressed by SC layers, resulting in reduced coupling(More)
The selective quantum dot ͑QD͒ nucleation on nanofaceted GaAs pyramidal facets is explored. The GaAs pyramids, formed on a SiO 2 masked ͑001͒ GaAs substrate, are characterized by well-defined equilibrium crystal shapes ͑ECSs͒ defined by three crystal plane families including ͕11n͖, ͕10n͖, and ͑001͒. Subsequent patterned QD ͑PQD͒ nucleation on the GaAs(More)
We report the device characteristics of stacked InAs/ GaAs quantum dots ͑QDs͒ with GaP strain-compensation ͑SC͒ layers grown by metal organic chemical vapor deposition. By inserting GaP SC layers within the stacked structures, decrease in the density of QDs by stacking QDs can be suppressed due to reduction of overall compressive strain within the stacked(More)
In order to reveal the constituents and their biological activities, we carried out a phytochemical study on Hedychium ellipticum Buch.-Ham. ex Sm. (Zingiberaceae). Ten labdane diterpenoids (1-10) were isolated from the rhizomes of H. ellipticum for the first time. Their structures were identified on the basis of spectroscopic analyses including(More)
  • D Shahrjerdi, N Nuntawong, G Balakrishnan, D I Garcia-Gutierrez, A Khoshakhlagh, E Tutuc +3 others
  • 2014
Articles you may be interested in Process temperature dependent high frequency capacitance-voltage response of ZrO 2 / GeO 2 /germanium capacitors Appl. Inhomogeneous distribution of dislocations in a SiGe graded layer and its influence on surface morphology and misfit dislocations at the interface of strained Si Si 0.8 Ge 0.2 Thermal stability of the HfO 2(More)
  • Claiborne O Mcpheeters, Edward T Yu, H W J Shockley, Queisser, K M W J Mazzer, I M Barnham +138 others
  • 2012
Simulations of thin film (~2.5 µm thick) InGaAs/GaAs quantum well solar cells with various back side reflective and planar, symmetric scattering structures used for light trapping have been performed using rigorous coupled-wave analysis. Two-dimensional periodic metal/dielectric scattering structures were numerically optimized for Airmass 0 photocurrent(More)