Homojunction-structured ZnO light-emitting diodes fabricated by dressed-photon assisted annealing

Abstract

We formed a p-n homojunction by implanting nitrogen ions, serving as a p-type dopant, into an n-type ZnO crystal. A forward bias current was injected into the crystal while irradiating it with light, bringing about Joule heating which annealed the crystal and changed the spatial distribution of the N-dopant concentration. This activated the N-dopant, causing its concentration distribution to be modified in a self-organized manner so as to be suitable for generating dressed photons. A light-emitting diode fabricated by this dressed-photon assisted annealing method showed electroluminescence at room temperature. In a device fabricated by annealing under irradiation with 407 nmwavelength light, at a forward bias current of 20 mA, the peak wavelength of the electroluminescence was 436 nm, the optical output power was 6.2 µW, and the external quantum efficiency was 1.1 × 10 −4 . The emission spectral profile depended on transitions from intermediate phonon states.

Si homojunction structured near-infrared laser based on a phonon-assisted process

“…Stimulated emission was produced via a two-step transition process driven by the light irradiation. This process is described below [4,5].…”

“…Stimulated emission was produced via a two-step transition process driven by the light irradiation. This process is described below [4,5].(i) First step: Dressed photons are generated by the light irradiation in regions where the dopant concentration in the p-n junction has a non-uniform spatial distribution. A dressed photon is a quasi-particle representing a coupled state due to the mutual interaction between a photon and an electron on the nanometer scale.…”

“…These domain boundaries have a shape and distribution suitable for efficiently inducing the phonon-assisted process described above during light emission [4,5].…”

Development of Zinc Oxide Spatial Light Modulator for High-Yield Speckle Modulation

“…In order to improve the practicality of our idea, we newly developed a transmissive-type device. Similar to the previous device, a commercially available ZnO single crystal, which was prepared by the hydrothermal growth method, was used, and nitrogen ions were doped into the crystal by using multi-step implantation [36]. The implantation is done by sequentially applying N + and N 2+ with acceleration energies in six steps from 20 keV to 600 keV.…”

Stable co-emission of UV, green and red light in ZnO thin films with rapid annealing treatment

“…Recently, its applications in solid light-emitting devices especially attract attention [11][12][13]. At room temperature, ZnO has a direct wide bandgap of ∼3.37 eV and a large exciton binding energy of 60 meV, which make it produce UV emission with a wavelength range from 370 to 390 nm originating from recombination of free excitons.…”