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Ultraviolet electroluminescence was demonstrated from a p-ZnO:As/n-SiC(6H) heterojunction light-emitting diode at room-temperature. The p-ZnO:As was fabricated by out-diffusion of arsenic atoms from a sandwiched GaAs interlayer on SiC substrate. The p-type doping was confirmed by both Hall and low-temperature photoluminescence measurements. Under forward bias, an intense ultraviolet emission centered at 384 nm was achieved from ZnO side of the diode. Furthermore, the light-output-current characteristic was determined to evaluate the high-efficiency electroluminescence performance of the diode. [ABSTRACT FROM AUTHOR]

Abstract: Heterojunction light-emitting diodes with ZnO/Si structure were fabricated on both high-resistivity (p) and low-resistivity (p+) Si substrates by metal–organic chemical vapor deposition technology. Fairly good rectifications were observed from the current–voltage curves of both heterojunctions. Ultraviolet (UV) and blue-white electroluminescence (EL) from ZnO layer were observed only from ZnO/p+-Si heterojunction under forward bias at room temperature (RT), while strong infrared (IR) EL emissions from Si substrates were detected from both ZnO/p-Si and ZnO/p+-Si heterojunctions. The UV and IR EL mechanisms have been explained by energy band structures. The realization of RT EL in UV–visible and IR region on Si substrate has great applicable potential for Si-based optoelectronic integrated circuits. [Copyright &y& Elsevier]

Abstract: The n-ZnO/i-NiO/n-GaN isotype heterojunction diode was fabricated by metal organic chemical vapor deposition (MOCVD) on the n-GaN/sapphire substrate. The current–voltage (I–V) measurement showed typical rectification characteristics with a turn-on voltage of 2.5V. An ultraviolet emission peak around 363nm was observed from the EL spectra at room temperature. High ultraviolet light extraction efficiency was proved by a superlinear curve of the intensity ratio of ultraviolet to visible emission. The mechanism of electroluminescence has been tentatively elucidated in terms of band diagrams of the heterojunction. [Copyright &y& Elsevier]

We fabricated the Ultraviolet light-emitting diode (LED) based on n-ZnO/i-NiO/p-Si heterostructure by metal-organic chemical vapor deposition (MOCVD). The device exhibited diode-like rectifying characteristics with a turn-on voltage of 3.2 V. The NiO film with high resistance state and [200] preferred orientation acted as an electron blocking layer, which produced a larger ZnO/NiO conduction band offset of 2.93 eV than that of ZnO/Si (0.30 eV). Under forward bias, prominent ultraviolet emissions peaked around 375 nm accompanying with rather weak blue–white emissions peaked around 480 nm were observed at room temperature. Furthermore, the mechanism of the electroluminescence was tentatively discussed in terms of the band diagram of the diode. [ABSTRACT FROM AUTHOR]

The n-InN/p-NiO/GaN heterojunction was fabricated by using plasma-assisted molecular beam epitaxy (PAMBE) combined with radio frequency magnetron sputtering. The device exhibited typical rectification characteristic with a turn-on voltage of ~1.5 V. Under forward bias, a dominant near infrared emission (NIR) peaked around 1565 nm was detected at room temperature. The NIR emission was attributed to the band-edge emission of InN film according to the photoluminescence spectrum of InN layer. Furthermore, the mechanism of the current transport and light emission was tentatively discussed in terms of the band diagrams of the heterojunction. [ABSTRACT FROM AUTHOR]

We fabricated the light-emitting diodes (LEDs) consisting of n-InN/p-NiO/p-Si heterostructure by using plasma-assisted molecular beam epitaxy (PAMBE) combined with radio frequency (RF) magnetron sputtering. The device exhibited diode-like rectifying current–voltage characteristics and had a turn-on voltage of 2.0 V. Under forward bias, a prominent narrow near infrared (NIR) emission peaked around 1565 nm was observed at room temperature. The NIR emission was demonstrated to come from the band-edge emission of InN layer. Moreover, the study of the LED in terms of the stability and efficiency were also discussed in detail. [ABSTRACT FROM AUTHOR]

We fabricated the light-emitting diodes (LEDs) consisting of n-ZnO/p-NiO/p-Si heterostructure by using metal-organic chemical vapor deposition (MOCVD) combined with radio frequency (RF) magnetron sputtering. The devices exhibited diode-like rectifying current–voltage characteristics and had a turn-on voltage of 6.8 V. Under forward bias, a prominent broad emission peaked around 400–650 nm was observed at room temperature. The asymmetric electroluminescence (EL) spectra were consisted of two apparent bands, which located at 420 and 495 nm corresponding to the violet and green luminescence, respectively. Furthermore, the mechanism of the light emission was tentatively discussed in terms of the band diagrams of the heterojunction. [ABSTRACT FROM AUTHOR]

Ultraviolet light-emitting diodes (LED) based on n-ZnO/NiO/p-GaN were realized by metal-organic chemical vapor deposition (MOCVD). The devices exhibited diode-like rectifying current–voltage characteristics and had a turn-on voltage of 7.5 V. High quality NiO film as an electron blocking layer inserted between the ZnO and GaN films showed high resistance state with preferred [1 1 1] orientation, which produced a larger ZnO/NiO conduction band offset of 2.93 eV than that of ZnO/GaN (0.15 eV). The electroluminescence spectra of the n-ZnO/i-NiO/p-GaN heterostructure demonstrated that electrons were effectively confined in the ZnO active region, and thus leading to the enhancement of the excitonic emission from the ZnO side. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, n-ZnO single microwire/p+-Si heterojunction LEDs are fabricated using the transparent conductive ITO film as an electrode. A distinct UV emission resulting from free exciton recombination in a ZnO single microwire is observed in the electroluminescence. Size difference of ZnO single microwire shows significant influence on emission efficiency. The EL spectra of n-ZnO single microwire/p-Si heterostructure exhibited relatively stronger UV emission which was compared with the EL spectra of n-ZnO single nanowire/p-Si heterostructure and n-ZnO film/p-Si heterostructure, respectively. [Copyright &y& Elsevier]

Abstract: ZnO-based heterojunction light emitting diodes (LEDs) with MgZnO barrier layer had been fabricated on the p-Si substrate by metal-organic chemical vapor deposition (MOCVD) technology. The current–voltage (I–V) characteristics exhibited a typical p–n diode behavior. Both ultraviolet (UV) and visible emissions could be detected in the electroluminescence (EL) measurement. The result was compared with the EL spectrum of n-ZnO/p-Si heterojunction LED without MgZnO barrier layer. An improved light extraction efficiency by about 31% was realized owing to the current-blocking effect of MgZnO layer. The result indicated that MgZnO barrier layer can prevent the electrons as expected and realize electron–hole recombination in ZnO layer effectively. [Copyright &y& Elsevier]

Abstract: In this paper, we proposed a new p-type ZnO doping method with metal organic chemical vapor deposition (MOCVD) technology by inserting a GaAs interlayer between substrate and ZnO epitaxial layer. The doping concentration of p-type ZnO film is able to be controlled by adjusting the thickness of the GaAs interlayer. With this method, we fabricated n-ZnO/p-ZnO:As homojunction light-emitting diode (LED) on ITO-glass substrate pre-coated with 20nm GaAs interlayer. The device exhibits a typical rectifying behavior by current–voltage (I–V) measurement. When the device is forward biased, UV–vis electroluminescence (EL) emissions can be observed clearly. [Copyright &y& Elsevier]

Abstract: ZnO film was firstly prepared by PA-MOCVD method on the substrate pre-coated with GaAs interlayer. Hall measurement found that the GaAs interlayer had important effects on the electrical behavior of the ZnO film. It could make the ZnO film convert to p-type conductivity. The XPS results confirmed that the acceptor was arsenic. And the acceptor level was 130meV above the ZnO valence band maximum. Low-temperature PL measurement was introduced to investigate the optical properties of both as-grown n-type and arsenic doped p-type ZnO films. Then, based on this technology, ZnO homojunction light emitting device (LED) was fabricated with arsenic doped p-type ZnO and unintentionally doped n-type ZnO on GaAs/p+-Si substrate. Its current–voltage (I–V) character showed a typical rectification behavior, which was different from the n-ZnO/p+-Si structure. The UV–visible (385–580nm) electroluminescence was detected under relatively low current injection condition from the n-ZnO/p-ZnO/p+-Si LED. [ABSTRACT FROM AUTHOR]