Localized luminescence centers of InGaN

Kanie, Hisashi; Tsukamoto, Nobuo; Koami, Hikari; Kawano, Teruhiko; Totsuka, T.

doi:10.1016/s0022-0248(98)00155-9

Cited by 16 publications

(4 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…InGaN shows several characteristic emission properties. Double or multi peaked CL spectra with a separation of more than 10 nm were observed from the InGaN microcrystals [12,13]. A similar double peaked CL spectrum is observed from the epitaxial InGaN layer grown thicker than the critical thickness on the GaN buffer layer [10,11].…”

supporting

confidence: 60%

Excitation energy transfer between luminescent centers of microcrystalline InGaN

Kanie

Yoshimura

2003

phys. stat. sol. (c)

View full text Add to dashboard Cite

PACS 61.72.Ji, 71.55.Eq, 78.60.Hk InGaN microcrystals were grown by nitridation of gallium and indium sulfide. Cathodoluminescence (CL) image observation of InGaN microcrystals at room temperature was performed under a scanning electron microscope at 3-5 kV with a beam diameter of 10 nm equipped with a monochromator. Highspatial-resolution monochromatic CL images composited with secondary electron microscope images showed each facet has uniform but different CL spectra, such as single or double peaked spectra at 420 and 460 nm. From the width of a dark zone and bright zone at the fringe of the facet in the monochromatic CL images taken at the two wavelengths the length of the excitation energy transfer was estimated as the diffusion length of the excited carriers. The ratios of the lifetimes of the radiative and nonradiative process of the excited carriers are calculated from the estimated diffusion lengths. , so the theoretical limit of efficiency ranges from 60 to 68% at the highest, though empirically it has been reported that the highest theoretical efficiency is about 38% [2]. To improve the efficiency we must understand the properties, such as density, cross section, lifetime and the atomic structure of the radiative and nonradiative centers in addition to the emissin mechanism [3,4]. The lifetime of excited carriers may be calculated by the diffusion length estimated from the width of a dark zone (energy transfer to the nonradiative center) in CL images [5,6]. InGaN shows several characteristic emission properties. Double or multi peaked CL spectra with a separation of more than 10 nm were observed from the InGaN microcrystals [12,13]. A similar double peaked CL spectrum is observed from the epitaxial InGaN layer grown thicker than the critical thickness on the GaN buffer layer [10,11]. The depth profile of CL spectrum is surveyed with an increase in the acceleration voltage and the double peaked spectra are measured and explained not by the quantum dot like In rich or phase separation region [3,4], but by the stress relaxation toward the growth direction confirmed by X-ray diffraction [10]. The low energy luminescence is attributed to the relaxed InGaN layer near the surface and the higher energy luminescence to the coherent InGaN layer on the GaN buffer layer, although X-ray diffraction data showed that the InGaN layer relaxed with the In content keeping at the same level [10]. The luminescence center has feature of a deep localized center, such as a broad bandwidth. The emission process of the double peaked CL spectra may be universal for InGaN. As the emission process of InGaN microcrystals is not well understood, however, we tentatively assign the observed luminescence peaking at 420 nm to a luminescence center at 420 nm and at 460 nm to the cen-

show abstract

supporting

confidence: 60%

Excitation energy transfer between luminescent centers of microcrystalline InGaN

Kanie

Yoshimura

2003

phys. stat. sol. (c)

View full text Add to dashboard Cite

show abstract

“…The particular physical properties of InGaN alloys with In concentrations x < 0.1 used for quantum wells in GaN matrices are the strong localization of excitons (Chichibu et al ., 1996; Kanie et al ., 1998; Wetzel et al ., 1998a) and the strong band gap bowing (nonlinear change of the band gap due to a change in the chemical composition) (McCluskey et al ., 1998; Wetzel et al ., 1998b). The localization of carriers has been explained: (i) by In concentration fluctuations in the alloy (Narukawa et al ., 1997; O'Donnell et al ., 1999); (ii) as an intrinsic effect due to hole localization at the In atom even in a homogeneous alloy (Bellaiche et al ., 1999); or (iii) by piezoelectric fields caused by the mismatch‐induced strain (Im et al ., 1998).…”

Section: Examples Of Applicationsmentioning

confidence: 99%

Cathodoluminescence in transmission electron microscopy

Strunk

Albrecht

Scheel

2006

Journal of Microscopy

View full text Add to dashboard Cite

We describe a cathodoluminescence spectrometer that is attached to an analytical transmission electron microscope. After a brief consideration of the set-up and the peculiarities of recording spectra and of mapping defect distributions in panchromatic and monochromatic cathodoluminescence, we discuss two examples of applications. Emphasis is placed on the potential for obtaining novel information about materials and processes on a microscopic and a nanoscopic scale by combining cathodoluminescence with the structural and chemical information for the same site of the specimen. We select an example concerning the role of In distribution in light emission from InGa/GaN quantum wells and a second one concerning the analysis of the initial electron radiation damage of Cu(In,Ga)Se(2) photovoltaic films.

show abstract

“…and Ga 2 S 3 by NH 3 results in low yield due to low reaction efficiency [11,12]. Simple and convenient synthetic routes are needed for preparing the GaN nanoparticles.…”

Section: Introductionmentioning

confidence: 99%