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The electrical properties of high-purity 4H–SiC epitaxial layers are investigated. The current density versus applied voltage curves shows that some specimens have space charge limited transport behavior. Lampert–Mark model for trap-controlled electron transport in semi-insulating materials demonstrated the presence of an intragap state at 0.26 eV below the conduction band. Photodeep level transient spectroscopy has confirmed the presence of a deep level at about 0.3 eV below the conduction band only in samples with non-Ohmic behavior. Cathodoluminescence imaging has revealed the presence of high luminescent areas related to stacking faults (SFs) under the devices showing non-Ohmic behavior. The presence of single-layer SFs was detected by cathodoluminescence spectroscopy due to the typical emission at 2.95 eV. Thus, we demonstrated that the SFs modified the charge transport from Ohmic conduction to space charge limited conduction of the affected samples. [ABSTRACT FROM AUTHOR]

Investigates the defective states induced in floating zone silicon by the heavy diffusion of dopants by means of the electron beam-induced current (EBIC) method. Evolution of the electrical and morphological properties of the induced defects; Role of aluminum in the electrical activity of bulk defective states; Sample mounting geometries utilized for EBIC analyses.

Presents a study which obtained the diffusion length of minority in n-type floating-zone silicon samples with the electron-beam-induced current technique in planar configuration. Background on the moment method; Experimental procedures; Results of the study.

We demonstrate that the process of local oxidation of surfaces by atomic force microscopy (AFM) can be upscaled in a straightforward way by using a solid support with multiple protrusions as the cathode electrode. A metallized digital video disk DVD polymeric support has been used as a stamp to generate an array of features of variable length and 100 nm in width on a silicon surface covering a 5×6 mm[sup 2] region. The parallel patterning process involves the formation of as many liquid bridges as there are protrusions in the stamp. The growth rate of the parallel local oxides is slightly smaller than the one obtained by AFM experiments. Nonetheless, results from AFM local oxidation experiments can be readily extended to parallel oxidation which in turn opens the possibility of patterning centimeter-square regions with 10 nm motives. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The optical activity of Er-doped silicon is related to the presence of defects which enhance the typical radiative transition at 0.8 eV but whose nature and properties are still largely unknown. We have investigated the deep levels present in Er-doped liquid phase epitaxy silicon to identify the traps possibly related to the luminescence. Among the observed levels, two minority carrier traps labeled E2 (E[sub C]-0.20 eV) and E3 (E[sub C]-0.39 eV), and one majority carrier trap labeled H1 (E[sub v]+0.32 eV) are good candidates for the material optical activity. The onset of luminescence occurs after a thermal treatment and is accompanied by a high space charge density localization at the epilayer-substrate interface. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Hydrogenated nanocrystalline silicon (nc-Si:H) is a multiphase, heterogeneous material, composed of Si nanocrystals embedded in an amorphous matrix. It has been intensively studied recently due to very promising photovoltaic and optoelectronics applications. The present paper aims to study electronic transitions in nc-Si:H grown by Low Energy Plasma Enhanced Chemical Vapor Deposition by Surface Photovoltage Spectroscopy. The study of several thin films grown at different conditions and the comparison with recently published computational studies allowed us to advance a hypothesis on the defect structure responsible for electronic transitions in nc-Si:H. [ABSTRACT FROM AUTHOR]

Bowing parameter and intra gap states have been measured on good quality undoped and n-type Si doped InGaN layers, by surface photovoltage spectroscopy (SPS). Bowing parameter calculations have been done with consideration of strain and relaxed nature of InGaN layers. Si donor levels have been measured by SPS on layers with different indium content. Free carrier concentration and Si donor level variations as a function of In content have been analysed. It has been found that the interaction between In and Si plays a fundamental role in Si doping process in InGaN. [ABSTRACT FROM AUTHOR]

Point and extended defects introduced in p-type Cz Si by oxygen precipitation and plastic deformation have been investigated with electrical and optical methods. Different materials (oxygen precipitated and/or deformed Cz Si and Fz Si) were examined in order to separate the role of oxygen precipitation, plastic deformation, and metallic contamination on the radiative and nonradiative electronic transitions at defect centers. A deep hole trap, named T1, has been associated with dislocation-related impurity centers; additional deep traps have been related to contamination by grown-in transition metals and to clusters involving oxygen atoms. [ABSTRACT FROM AUTHOR]

Time-resolved cathodoluminescence (TRCL) and photocurrent (PC) spectroscopies have been applied to the study of the yellow band of Si-doped GaN. Measurements carried out combining both techniques unambiguously reveal the complex nature of this broad emission and confirm that different deep defect levels are involved in the observed luminescence. Five emission bands centered at 1.89, 2.03, 2.16, 2.29, and 2.38 eV were found by steady state and time-resolved CL investigations, while PC spectra showed four transitions at about 2.01, 2.14, 2.28, and 2.43 eV. The behavior of the deep-level emissions intensity as a function of the excitation pulse width as well as their decay times were investigated by TRCL. A decay time of 245 μs was measured for the 2.29 eV emission band, while longer decay times of 315 and 340 μs were found, respectively, for the 2.16 and 2.38 eV bands, in agreement with TRCL spectra. The appearance of the 2.03, 2.16, 2.29 eV and 2.38-2.43 eV peaks both in PC and CL spectra suggests that these bands are related to deep acceptor to band transitions, as supported by the single exponential character of the corresponding decay transients. [ABSTRACT FROM AUTHOR]

Photoluminescence (PL) and deep level transient spectroscopy (DLTS) measurements were used to study the origin of optical emissions in the 0.8-1.0 eV region of selected oxygen precipitated and dislocated silicon samples. It was shown that the D1 band, present in both types of samples, is the convolution of different sub-bands, narrowly spaced between 0.802 and 0.820 eV. The emission at 0.807 eV, assigned in the literature to dislocations, was found only in samples where dislocations were intentionally generated by plastic deformation or induced by the clustering of self-interstitials generated during the growth of oxide precipitates. A comparison of the results of PL, DLTS, and optical DLTS measurements allows the assignment of levels involved in the radiative recombination processes. [ABSTRACT FROM AUTHOR]