Temperature behavior of visible and infrared electroluminescent devices fabricated on erbium-doped GaN

Abstract

Visible and infrared (IR) rare-earth-activated light emission has been obtained from Er-doped GaN electroluminescent devices (ELD). The ELD consists of an in-situ Er-doped GaN layer grown on either a sapphire or silicon (Si) substrate. The temperature dependence of the light emission and the current conduction is reported. The EL spectrum shows two main visible peaks at 537 and 558 nm and a group of closely spaced IR peaks clustered around 1550 nm. The 558 nm visible transition is dominant below 250 K, whereas the 537 nm transition is dominant at higher temperature peaking at 300 K. Temperatures from 240-500 K have minimal effect on IR emission intensity. A simple model consisting of two back-to-back Schottky diodes explains the current-voltage dependence. The effect of Er doping and substrate type on carrier transport is investigated as a function of voltage and temperature. Specifically, there is evidence that an Er-related defect is responsible for carrier generation at temperatures above 300 K. The effect of bias polarity on spatial confinement of the light emission in different areas of the devices is discussed. The model indicates that both electric field intensity and current density are important in producing light emission. The model also accounts for the uniformity of the emission under the electrodes when considering the type of substrate used for GaN:Er device growth.

Rare-earth-doped GaN: growth, properties, and fabrication of electroluminescent devices

“…8(a), except the resistor becomes the series resistance of the entire device. The carrier transport of the resistor is somewhat complicated and is considered in more detail elsewhere [39]. Fig.…”

“…The applicability of GaN:RE materials to infrared ELDs has been shown in the previous sections. GaN:Er is of special interest since it has been shown to be relatively immune to the thermal quenching [39] seen in other Er-doped semiconductors and has the ability to incorporate significant concentration [27] of RE ions without precipitation and without quenching the photoluminescence or electroluminescence intensity. These properties, in conjunction with the fact that GaN is a semiconductor and can provide charge carrier excitation of the Er ions (unlike insulators such as SiO :Er), meet the key requirements for an electrically pumped waveguide amplifier.…”

Thermal doping of rare-earth ions in gallium nitride

“…GaN is particularly suitable as a host material for such applications because its wide band gap suppresses luminescence quenching at room temperatures [3]. Red emission has been demonstrated from europiumdoped GaN [4,5], green from erbium-doped GaN [6][7][8] as well as from terbium-doped GaN [9,10] and blue from thulium-doped GaN [7]. Both photo-pumped and electrically pumped luminescence has been demonstrated [13].…”

Dependence of implantation-induced damage with photoluminescence intensity in GaN:Er

“…Er-doped GaN is currently being widely studied because of the potential applications in optical communications and full color displays [1][2][3]. Er ions are usually introduced into GaN either during growth or by ion implantation [4,5].…”