Temperature-dependent Schottky barrier inhomogeneity of Ni/n-GaAs diodes

We have reported a study of the I–V characteristics of Ni/n-GaAs Schottky barrier diodes (SBDs) in a wide temperature range of 60–320 K by a step of 20 K, which are prepared by magnetron DC sputtering. The experimental I–V data of the device quite well obey the thermionic emission model at 300 and 320 K, respectively. The ideality factor and barrier height values have changed by change of the sample temperature, the case has been attributed to the presence of the lateral inhomogeneities of the barrier height. The barrier inhomogeneity has been explained by the Gaussian distribution models of barrier heights suggested by some authors, Y.-L. Jiang et al. [Chin. Phys. Lett. 19, 553 (2002)]; Y.-L. Jiang et al. [J. Appl. Phys. 93, 866 (2003)], and S. Chand, J. Kumar [Appl. Phys. A 65, 497 (1997)]. It has been seen that the SBH inhomogeneity of our Ni/n-GaAs SBD can be well described by Gaussian distribution model suggested by Y.-L. Jiang et al. [Chin. Phys. Lett. 19, 553 (2002)]; Y.-L. Jiang et al. [J. Appl. Phys. 93, 866 (2003)] over whole measurement temperature range. Moreover, the modified ln($I_{0}/T ^{2}$) versus $1/k(T+T_0^\ast)$ plot is obtained using a method developed for T0 anomaly in the literature. Richardson constant value of 3.37 A cm-2 K-2 for n-type GaAs was obtained from the modified Richardson plot

Huge intrathoracal cystic mass restricted by dense calcification

PubMed: 19917804[No abstract available

The effects of the time-dependent and exposure time to air on Au/epilayer n-Si Schottky diodes

A study on Au/n-Si Schottky barrier diodes (SBDs) parameters with and without thin native oxide layer fabricated on n-type Si grown by LPE (Liquid-Phase Epitaxy) technique has been made. The native oxide layer with different thicknesses on chemically cleaned Si surface was obtained by exposing the Si surfaces to clean room air before metal evaporation. The native oxide thicknesses of samples D2, D3, D4 and D5 are in the form D2 < D3 < D4 ≤ D5 depending on the exposing time. It has been seen that the value of the barrier height Φb of samples D2 (0.64 eV), D3 (0.66 eV), D4 (0.69 eV) and D5 (0.69 eV) increases with increasing the exposure time and tends to that of the initial sample D1 (the initial sample, 0.74 eV), and thus also their I − V curves. Especially, the experimental results related to the exposure time of the surfaces to clean air are close in agreement with recently results reported for the HF-treated n-Si surface during initial oxidation in air. Furthermore, it has been determined experimentally that ageing of the Au contacts on the oxidized epilayer Si leads to barrier height values close to those measured for Au on chemically cleaned surfaces

The effect of exposure time to clean room air on characteristic parameters of Au/Epilayer n-Si Schottky diodes

A study has been made on determination and comparison of current-voltage (I-V) and capacitance-voltage (C-V) characteristics parameters of Au/n-Si Schottky barrier diodes (SBDs) with and without thin native oxide layer fabricated on n-type Si grown by LPE (Liquid-phase Epitaxy) technique. The native oxide layer with different thicknesses on chemically cleaned on Si surface were obtained by exposing the surfaces to clean room air before evaporating metal. The native oxide thicknesses of samples D2, D3, D4 and D5 are in the form D2 < D3 < D4 \leq D5, depending on the exposing time. It has been seen that the values of barrier height Fb of samples D2(0.64 eV), D3(0.66 eV), D4(0.69 eV) and D5(0.69 eV) with the interfacial layer increased with increasing the exposure time and tended to that of the initial sample D1 (nonoxidezed sample, 0.74 eV), and thus also their I-V and C-V curves. The reverse current of sample D1 showed slight nonsaturating behavior. This ''soft'' behavior has been ascribed to the spatial inhomogeneity in the barrier heights at the MS interface. In particular, reverse bias curves of samples D2, D3, D4 and D5 have shown excellent saturation which may be attributed to the passivation of the semiconductor surface states by the native oxide layer which reduces the penetration of the wave functions of electron in the metal into the semiconductor. Especially, the I-V characteristics and experimental parameters of our devices are in agreement with recently reported results revealed by the pulsed surface photovoltage technique for the electronic properties of the HF-treated Si surface during initial oxidation in air

Histological investigation of the effects of tenoxicam on pulmonary complications of pneumoperitoneum - Tenoxicam reduces lung injuries caused by pneumoperitoneum

Objectives. Pneumoperitoneum increases intra-abdominal pressure and generates oxidative stress, which mediates tissue injury. One of the causes of oxidative stress production is an inflammatory reaction. Taking this into consideration, the current animal study was designed, using tenoxicam before a laparoscopy procedure in order to ascertain whether tenoxicam can prevent lung injury caused by pneumoperitoenum. Material and Methods. Fourteen female Wistar rats were randomly divided into two groups: the tenoxicam group (seven rats) and the control group (seven rats). The tenoxicam group was given two doses (totalling 0.5 mg/kg) of intraperitoneal tenoxicam, and the control group was given 0.5 cc of 0.9% NaCl, 12 hours and 1/2 hour before the operation. Under intra-peritoneal anesthesia, a Veress needle was placed in the peritoneal cavity and a 15 mm-Hg pneumoperitoneum was established and maintained for 20 minutes; the peritoneal gas was then desufflated. The lungs were resected at the 180 th minute from the beginning of the operation and were evaluated histopathologically. Histopathological evaluations including intra-alveolar hemorrhage, alveolar edema, congestion and leukocyte infiltration were carried out for both groups. Results. A statistical comparison of the evaluation scores revealed significant differences between the two groups for intra-alveolar hemorrhage (p = 0.007), alveolar edema (p = 0.023) and congestion (p = 0.005) and a non-significant difference for leukocyte infiltration (p = 0.114). Conclusions. Pneumoperitoneum causes injuries to lung tissue; tenoxicam reduces that damage and protects the lungs by decreasing intra-alveolar hemorrhage, alveolar edema and congestion. © Copyright by Wroclaw Medical University