Case ID: M09-043P

Published: 2011-01-25 09:10:12

Last Updated: 1677134864


Cun-Zheng Ning
Anlian Pan

Technology categories

Energy & PowerPhysical Science

Licensing Contacts

Shen Yan
Director of Intellectual Property - PS
[email protected]

Continuous Laterally Varying II-VI Alloys and Applications

Bandgap engineering in semiconductors can be used to produce
optoelectronic devices, such as photovoltaic devices and lasers for operation in
different wavelengths. A new bandgap (or wavelength) can be achieved by alloying
together two (or more) semiconductor materials of different bandgaps. However,
existing methods of growing planar epitaxial heterostructures of semiconductors
on crystalline substrates invariably require limited lattice constant mismatch
(or a method to relieve the strain developed by lattice mismatch). Consequently,
this requirement has provided the primary obstacle to manufacturing
semiconductor-based optoelectronic devices with controllable and widely variable
(tunable) operating wavelengths. Recent methods employing nanowire-based
technology have made great strides in overcoming this obstacle, greatly relaxing
this restriction to allow for the growth of materials with mismatch as high as
8%, or even removing this restriction altogether. Notwithstanding these
successes, there remains an important challenge of achieving a full-range of
alloy composition variation within a single substrate in a single run of growth.

Researchers at Arizona State University have developed II-VI
semiconductor structures with laterally varying bandgaps across a substrate,
allowing broad wavelength operation ranges from UV to IR for optoelectronic
devices. The entire spatial extension of nanomaterials (on a given substrate)
can be subdivided into multiple regions laterally that are electronically
separated from each other, so that separate electrical contacts can be fashioned
for each region (or band). This can allow extraction (or injection) of electrons
and holes separately from other regions (bands). This unprecedented bandgap
range on a single substrate could enable a wide variety of applications.

Potential Applications

  • Lateral multi-junction solar cells
  • Wavelength tunable laser arrays
  • Broadband light sources for solid state lighting and

  • Multicolor detectors

Benefits and Advantages

  • Allows Wavelength Selective Absorption over the Entire
    Solar Spectrum on a single substrate, potentially reaching the theoretical
    limit of solar cell efficiency.

  • Allows Extraction of Charged Carriers within the Same
    Energy Range in which the Charged Carriers are Created ? eliminates or largely
    reduces heat generation; provides for greatly increased device efficiency
    potential by minimizing loss

  • Provides Straightforward Preparation with Single Step

  • Offers Benefits of Nanowire-Based Technology ? functions
    with extremely wide bandgap tuning, provides channels for electronic
    conduction and waveguiding, and acts as gain/absorbing material