Ⅲ-nitride light-emitting diodes(LEDs)are now used almost everywhere,due to their energy-saving capability.In the near future,the vast majority of lighting sources will undoubtedly be based on LEDs.What future technol...Ⅲ-nitride light-emitting diodes(LEDs)are now used almost everywhere,due to their energy-saving capability.In the near future,the vast majority of lighting sources will undoubtedly be based on LEDs.What future technologies and applications can we expect from Ⅲ-nitride-based and particularly gallium nitride(Ga N)-based,materials and devices?展开更多
Light-emitting diodes are becoming the alternative for future general lighting applications,with huge energy savings compared to conventional light sources owing to their high efficiency and reliability.Polarized ligh...Light-emitting diodes are becoming the alternative for future general lighting applications,with huge energy savings compared to conventional light sources owing to their high efficiency and reliability.Polarized light sources would largely enhance the efficiency in a number of applications,such as in liquid-crystal displays,and also greatly improve contrast in general illumination due to the reduction in indirect glare.Here,we demonstrate light-emitting diodes presenting high-brightness polarized light emission by combining the polarization-preserving and directional extraction properties of embedded photonic-crystals applied to non-polar gallium nitride.A directional enhancement of up to 1.8-fold was observed in the total polarized light emission together with a high polarization degree of 88.7%at 465 nm.We discuss the mechanisms of polarized light emission in non-polar gallium nitride and the photonic-crystal design rules to further increase the light-emitting diode brightness.This work could open the way to polarized white-light emitters through their association with polarization-preserving down-converting phosphors.展开更多
Using one material system from the near infrared into the ultraviolet is an attractive goal,and may be achieved with(ln,AI,Ga)N.ThisⅢ-N material system,famous for enabling blue and white solid-state lighting,has been...Using one material system from the near infrared into the ultraviolet is an attractive goal,and may be achieved with(ln,AI,Ga)N.ThisⅢ-N material system,famous for enabling blue and white solid-state lighting,has been pushing towards longer wavelengths in more recent years.With a bandgap of about 0.7 eV,InN can emit light in the near infrared,potentially overlapping with the part of the electromagnetic spectrum currently dominated byⅢ-As andⅢ-P technology.As has been the case in these otherⅢ-V material systems,nanostructures such as quantum dots and quantum dashes provide additional benefits towards optoelectronic devices.In the case of InN,these nanostructures have been in the development stage for some time,with more recent developments allowing for InN quantum dots and dashes to be incorporated into larger device structures.This review will detail the current state of metalorganic chemical vapor deposition of InN nanostructures,focusing on how precursor choices,crystallographic orientation,and other growth parameters affect the deposition.The optical properties of InN nanostructures will also be assessed,with an eye towards the fabrication of optoelectronic devices such as light-emitting diodes,laser diodes,and photodetectors.展开更多
文摘Ⅲ-nitride light-emitting diodes(LEDs)are now used almost everywhere,due to their energy-saving capability.In the near future,the vast majority of lighting sources will undoubtedly be based on LEDs.What future technologies and applications can we expect from Ⅲ-nitride-based and particularly gallium nitride(Ga N)-based,materials and devices?
基金The experimental part of this work was performed at University of California,Santa Barbara.This study is based upon work partially supported as part of the‘Center for Energy Efficient Materials’at University of California,Santa Barbara,an Energy Frontier Research Center funded by the US Department of Energy,Office of Science,Office of Basic Energy Sciences under Award Number DE-SC0001009 and by the Solid State Lighting and Energy Center(SSLEC)at the University of California,Santa Barbara.
文摘Light-emitting diodes are becoming the alternative for future general lighting applications,with huge energy savings compared to conventional light sources owing to their high efficiency and reliability.Polarized light sources would largely enhance the efficiency in a number of applications,such as in liquid-crystal displays,and also greatly improve contrast in general illumination due to the reduction in indirect glare.Here,we demonstrate light-emitting diodes presenting high-brightness polarized light emission by combining the polarization-preserving and directional extraction properties of embedded photonic-crystals applied to non-polar gallium nitride.A directional enhancement of up to 1.8-fold was observed in the total polarized light emission together with a high polarization degree of 88.7%at 465 nm.We discuss the mechanisms of polarized light emission in non-polar gallium nitride and the photonic-crystal design rules to further increase the light-emitting diode brightness.This work could open the way to polarized white-light emitters through their association with polarization-preserving down-converting phosphors.
基金This work was supported by the Solid State Lighting and Energy Electronics Center at the University of California,Santa Barbara.
文摘Using one material system from the near infrared into the ultraviolet is an attractive goal,and may be achieved with(ln,AI,Ga)N.ThisⅢ-N material system,famous for enabling blue and white solid-state lighting,has been pushing towards longer wavelengths in more recent years.With a bandgap of about 0.7 eV,InN can emit light in the near infrared,potentially overlapping with the part of the electromagnetic spectrum currently dominated byⅢ-As andⅢ-P technology.As has been the case in these otherⅢ-V material systems,nanostructures such as quantum dots and quantum dashes provide additional benefits towards optoelectronic devices.In the case of InN,these nanostructures have been in the development stage for some time,with more recent developments allowing for InN quantum dots and dashes to be incorporated into larger device structures.This review will detail the current state of metalorganic chemical vapor deposition of InN nanostructures,focusing on how precursor choices,crystallographic orientation,and other growth parameters affect the deposition.The optical properties of InN nanostructures will also be assessed,with an eye towards the fabrication of optoelectronic devices such as light-emitting diodes,laser diodes,and photodetectors.
