Electrically and optically readable light emitting memories.

Electrochemical metallization memories based on redox-induced resistance switching have been considered as the next-generation electronic storage devices. However, the electronic signals suffer from the interconnect delay and the limited reading speed, which are the major obstacles for memory performance. To solve this problem, here we demonstrate the first attempt of light-emitting memory (LEM) that uses SiO2 as the resistive switching material in tandem with graphene-insulator-semiconductor (GIS) light-emitting diode (LED).

Local nanotip arrays sculptured by atomic force microscopy to enhance the light-output efficiency of GaN-based light-emitting diode structures.

In this work, local nanotip arrays on GaN-based light-emitting (LED) structures were fabricated through nano-oxidation using an atomic force microscope (AFM). The photoluminescence (PL) intensity of the InGaN/GaN multiple quantum wells (MQWs) active layer and the light extraction efficiency of the LED structure were enhanced by forming this nanotips structure to serve as a graded-refractive index layer, which is further validated by the finite-difference time-domain analysis. The PL emission peak of the MQWs active layer has a blue-shift phenomenon that is caused by a partial reduction of the strain on the InGaN well.

Direct formation of InN-codoped p-ZnO/n-GaN heterojunction diode by solgel spin-coating scheme.

In this work p-ZnO/n-GaN heterojunction diodes were directly formed on the Si substrate by a combination of cost-effective solgel spin-coating and thermal annealing treatment. Spin-coated n-ZnO films on InN/GaN/Si wafers were converted to p-type polarity after thermal treatment of proper annealing durations. X-ray diffraction (XRD) analysis reveals that InN-codoped ZnO films have grown as the standard hexagonal wurtzite structure with a preferential orientation in the (002) direction.

Transferable and flexible label-like macromolecular memory on arbitrary substrates with high performance and a facile methodology.

A newly designed transferable and flexible label-like organic memory based on a graphene electrode behaves like a sticker, and can be readily placed on desired substrates or devices for diversified purposes. The memory label reveals excellent performance despite its physical presentation. This may greatly extend the memory applications in various advanced electronics and provide a simple scheme to integrate with other electronics.

Efficient light harvesting by photon downconversion and light trapping in hybrid ZnS nanoparticles/Si nanotips solar cells.

A hybrid colloidal ZnS nanoparticles/Si nanotips p-n active layer has been demonstrated to have promising potential for efficient solar spectrum utilization in crystalline silicon-based solar cells. The hybrid solar cell shows an enhancement of 20% in the short-circuit current and approximately 10% in power conversion efficiency compared to its counterpart without integrating ZnS nanoparticles. The enhancement has been investigated by external quantum efficiency, photoluminescence excitation spectrum, photoluminescence, and reflectance to distinct the role of ZnS quantum dots for light harvesting.

Electroluminescence from ZnO/Si-nanotips light-emitting diodes.

A new and general approach to achieving efficient electrically driven light emission from a Si-based nano p-n junction array is introduced. A wafer-scale array of p-type silicon nanotips were formed by a single-step self-masked dry etching process, which is compatible with current semiconductor technologies. On top of the silicon nanotip array, a layer of n-type ZnO film was grown by pulsed laser deposition.

Transverse-junction superluminescent diodes at the 1.1 microm wavelength regime.

We demonstrate, for the first time to our knowledge, GaAs-based transverse-junction (TJ) superluminescent diodes (SLDs) that operate at a wavelength of 1.1 microm. Due to lateral current injection by use of TJ, specified as transverse carrier flow spread in each quantum well horizontally instead of vertical well-by-well injection, nonuniform carrier distribution can be minimized among different multiple quantum wells (MQWs), which is a problem in vertical-junction (VJ) SLDs whose electroluminescent (EL) spectrum is governed by the center wavelength of QWs near the p side.