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Quantum-size-controlled photoelectrochemical fabrication of epitaxial InGaN quantum dots

Nano Letters

Xiao, Xiaoyin; Fischer, Arthur J.; Wang, George T.; Lu, Ping L.; Koleske, Daniel K.; Coltrin, Michael E.; Wright, Jeremy B.; Liu, Sheng; Brener, Igal; Subramania, Ganapathi S.; Tsao, Jeffrey Y.

We demonstrate a new route to the precision fabrication of epitaxial semiconductor nanostructures in the sub-10 nm size regime: quantum-size-controlled photoelectrochemical (QSC-PEC) etching. We show that quantum dots (QDs) can be QSC-PEC-etched from epitaxial InGaN thin films using narrowband laser photoexcitation, and that the QD sizes (and hence bandgaps and photoluminescence wavelengths) are determined by the photoexcitation wavelength. Low-temperature photoluminescence from ensembles of such QDs have peak wavelengths that can be tunably blue shifted by 35 nm (from 440 to 405 nm) and have line widths that narrow by 3 times (from 19 to 6 nm).

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The Energy Frontier Research Center for Solid-State Lighting Science: Exploring New Materials Architectures and Light Emission Phenomena

Journal of Physical Chemistry C

Coltrin, Michael E.; Subramania, Ganapathi S.; Tsao, Jeffrey Y.; Wang, George T.; Wierer, Jonathan W.; Wright, Jeremy B.; Armstrong, Andrew A.; Brener, Igal B.; Chow, Weng W.; Crawford, Mary H.; Fischer, Arthur J.; Koleske, Daniel K.; Martin, James E.; Rohwer, Lauren E.

Abstract not provided.

Contribution of deep-level defects to decreasing radiative efficiency of InGaN/GaN quantum wells with increasing emission wavelength

Applied Physics Express

Armstrong, Andrew A.; Crawford, Mary H.; Koleske, Daniel K.

Deep-level optical spectroscopy (DLOS) and photoluminescence (PL) were used to understand the role of defects in reducing the internal quantum efficiency (IQE) of InxGa1-xN/GaN multiple quantum wells (MQWs) as the emission wavelength increased from approximately 450 to 530 nm, i.e., the "green gap". DLOS studies of light emitting diodes (LEDs) identified QW defects whose concentration increased significantly with increasing x. The effect of increased QW defect density on IQE was assessed by examining the PL of MQW samples. Green-emitting MQWs had lower IQE and required higher pump power to reach peak IQE, corroborating the important impact of enhanced non-radiative recombination at defects. © 2014 The Japan Society of Applied Physics.

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Results 51–75 of 203
Results 51–75 of 203