Eu-Doped GaN Films Grown by Phase Shift Epitaxy

Abstract

Phase shift epitaxy (PSE) is a dynamic thin film growth technique wherein constituent fluxes are pulsed with an adjustable phase shift. PSE enables the introduction of dopants during the optimum segment of the growth cycle. Eu-doped GaN films were grown with Ga and Eu shutters periodically opened and closed (with varying phase shift) while keeping N flux constant, so that the Ga and Eu coverage on surface during each cycle varies in a controlled way. The Eu concentration and photoluminescence (PL) efficiency are strongly influenced by the PSE parameters. Eu ions doped during high Ga coverage exhibit strong PL efficiency.

Eu3+ luminescence properties of Eu- and Mg-codoped AlGaN

“…Therefore, RE-doped nitride semiconductors with wide bandgaps have attracted attention for improving luminescence properties. Samples have been prepared through ion implantation and annealing [2,3], in addition to crystal growth through molecular beam epitaxy (MBE) [4][5][6][7][8] and organometallic vapor phase epitaxy (OMVPE) [9]. RGB-color-integrated RE-doped GaN thin film electroluminescence (EL) devices, and light-emitting high electron-mobility transistors (HEMTs) with spatially selective Eu doping region have been fabricated [10,11].…”

Self-Organized Eu-Doped GaN Nanocolumn Light-Emitting Diode Grown by RF-Molecular-Beam Epitaxy

“…However, in future, crystalline quality improvement may be achieved by optimization of growth condition. For GaN:Eu thin layer, although it high growth temperature, V/III ratio and phase shift epitaxy by shutter sequence led to improve the optical properties, but it strongly influenced the Eu concentration . Finally, we noted the Eu concentration (2 × 10 20 cm −3 ) at which the decay time began to decrease.…”

“…In the past decade, fabrication of InGaN‐based red LEDs has been challenging; however, high‐efficiency and high‐light output red LEDs have not been achieved because of generation of many misfit dislocations by a large lattice mismatch and reduction of overlap of electron and hole wave functions by a large piezoelectric field. Europium‐doped GaN (GaN:Eu) is one of the material candidates for realizing thermally stable red optical devices . It shows remarkable optical characteristics such as sharp line spectra and stability of emission wavelength against environmental temperature because each Eu ion behaves as a quantum dot owing to the 4f ‐ 4f electron transition in their inner shell.…”

p-type GaN grown by phase shift epitaxy

“…PSE doping of Eu in GaN under Ga-rich conditions has been previously reported 14 to yield a 10Â enhancement of Eu luminescence efficiency. In this paper, high hole concentration in Mg-doped GaN is achieved by adjusting the PSE doping window to suppress Mg self-compensation at high Mg concentration.…”

“…Hole concentration as high as 4.5 Â 10 18 cm À3 with an accompanying mobility of 1.2 cm 2 /VÁs has been achieved with MME. 10 MME and other similar growth schemes, [11][12][13][14] such as metal enhanced epitaxy (MEE), 11 alternatively saturate the surface with Ga and N fluxes, so that good quality film is achieved even at relatively low growth temperatures.…”