ZnO Green Light Emitting Diode

Shimizu, Ayumi; Kanbara, Minoru; Hada, Makoto; Kasuga, Masanobu

doi:10.1143/jjap.17.1435

Cited by 52 publications

(19 citation statements)

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“…SiO 2 layers of 100-nm thickness were deposited on select samples by plasma-enhanced chemical vapor deposition to study the effects of passivation. Prior to passivation, the surfaces of the samples were cleaned in 30% H 2 O 2 for 15 min., as suggested by Shimizu et al 8 Photoconductive decay was examined on two different time scales using separate measurement setups. Fast photoconductive transients of up to 1 sec were studied using pulsed laser excitation, where the ZnO photoconductor was biased in a resistive circuit, as is shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

Trap-related photoconductivity in ZnO epilayers

Murphy

Moazzami

Phillips

2006

J. Electron. Mater.

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A strong photoconductive response is observed for ZnO epilayers in the presence of both above bandgap and below bandgap photoexcitation. Photoexcitation for energies larger than the bandgap results in a photoconductive response with fast and slow time constants on the order of nanoseconds and larger than milliseconds, respectively. The fast and slow time constants are attributed to minority carrier recombination and slow escape of holes from traps, respectively. Photoexcitation in the visible spectral region, below the bandgap energy, results in slow rise and fall time constants on the order of minutes and hours. A model for the photoconductive response based on rate equations is presented providing an accurate fit to measured photoconductivity data. The rate equation model suggests the presence of hole trap levels in the energy range of 0.6 eV to 1.0 eV relative to the valence bandedge. The passivation of the ZnO surface with SiO 2 shows significantly reduced photoconductive transient decay time constants, suggesting a significant reduction of deep surface defects on the ZnO material.

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Section: Methodsmentioning

confidence: 99%

Trap-related photoconductivity in ZnO epilayers

Murphy

Moazzami

Phillips

2006

J. Electron. Mater.

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“…EL was observed under forward bias and the spectrum consisted of a band with a maximum at 430 nm. To favor hole injection into ZnO and thereby promote emission in that material (because ZnO is highly n-type and electron injection into GaN dominates over the hole injection from GaN into ZnO), Alivov et al [113] Because of the difficulties associated with p-n junctions, electroluminescence properties of ZnO have been explored by metal-insulator-semiconductor (MIS) structures [115][116][117]. Shimizu et al [118] fabricated a MIS diode with an insulating ZnO layer by subjecting the ZnO crystal to H 2 O 2 .…”

Section: Light Emitting Devicesmentioning

confidence: 99%

Preparation and properties of ZnO and devices

Izyumskaya

Avrutin

Özgür

et al. 2007

Physica Status Solidi (b)

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ZnO has gained interest in part because of its large exciton binding energy (60 meV), good for lasing with low threshold. The renewed interest in ZnO is fuelled by availability of high quality substrates, reports of p-type conductivity, and ferromagnetic behavior when doped with transitions metals. The field is also fuelled by theoretical predictions and perhaps experimental confirmation of ferromagnetism at room temperature for potential spintronics applications. Despite great strides there are still many challenges, the chief among them is the attainment of reproducibly low resistivity p-type ZnO. While ZnO already has many industrial applications owing to its piezoelectric properties and bandgap in the near UV, its applications to optoelectronic devices utilizing electrical injection has not yet been put to practice mainly due to the lack of p-type epitaxial layers. This review provides a discussion of some of the growth issues of ZnObased epitaxial and heteroepitaxial layers and their use in a variety of devices.

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“…[48] They have been used as an excitation source for yellow phosphors in white LEDs. [49,50] 8. Development of Nitride-Based LDs and Other Devices…”

Section: Brief History Of Nitride-based Blue Ledsmentioning

confidence: 99%