Pores in p-type GaN by annealing under nitrogen atmosphere: formation and photodetector

Author(s):  
Rongrong Chen ◽  
Jie Liu ◽  
Bo Feng ◽  
Hongyan Zhu ◽  
Di Wang ◽  
...  
Keyword(s):  
2002 ◽  
Vol 17 (5) ◽  
pp. 1019-1023 ◽  
Author(s):  
S.J. Yang ◽  
T.W. Kang ◽  
T.W. Kim ◽  
K.S. Chung

The dependences of the properties of Au/Ni/Si/Ni contacts, deposited on p-GaN epilayers by using electron-beam evaporation, on the Si layer thickness and the annealing temperature were investigated with the goal of producing contacts with low specific resistances. The results of the current–voltage (I–V) curves showed that the lowest specific contact resistance obtained for the Au/Ni/Si/Ni contact with a 1200-Å- thick Si layer on p-type GaN annealed at 700 °C for 1 min in a nitrogen atmosphere was 8.49 × 10-4 Ω cm2. The x-ray diffraction (XRD) measurements on the annealed Au/Ni/Si/Ni/p-GaN/sapphire heterostructure showed that Ni3Si, GaAu, and NiGa layers were formed at the Au/Ni/Si/Ni/p-GaN interfaces. While the intensities corresponding to the Ni3Si layer decreased with increasing annealing temperature above 700 °C, those related to the GaAu and the NiGa layers increased with increasing temperature. These results indicate that the Au/Ni/Si/Ni contacts with 1200-Å-thick Si layers annealed at 700 °C hold promise for potential applications in p-GaN-based optoelectronic devices.


2013 ◽  
Vol 1538 ◽  
pp. 123-129 ◽  
Author(s):  
Monika Arasimowicz ◽  
Maxime Thevenin ◽  
Phillip J. Dale

ABSTRACTCu2ZnSnSe4 p-type semiconductors currently investigated for use in thin film solar cells can be synthesized by firstly depositing a metallic precursor and secondly annealing the precursor in selenium vapor. Differently stacked Cu-Sn-Zn metallic precursors were characterized after a soft annealing at 350°C under nitrogen atmosphere. For the stack where the Sn and Zn were in direct contact with sufficient Cu to form a stable alloy, a bi-layered structure consisting of Cu-Sn on the bottom and Cu-Zn on the top was formed. Contrarily, when Zn was not in direct contact with Cu, the metals diffused to form a stable alloy and the system segregates horizontally, forming a mixed columnar structure. These two types of precursors were selenized under exactly the same conditions to form kesterite absorbers for solar cell devices. Using this approach the improvement from 0.44% power conversion efficiency for the bi-layered precursor to 4.5% for the mixed precursor was achieved.


1990 ◽  
Vol 181 ◽  
Author(s):  
Sailesh Chittipeddi ◽  
Michael J. Kelly ◽  
Charles M. Dziuba ◽  
Anthony S. Oates ◽  
William T. Cochran

ABSTRACTIn this paper we characterize the thin film formed by rapid thermal anneal of a magnetron sputtered titanium film in a nitrogen atmosphere. The barrier properties of this material have been characterized for both n- and p-type junctions in our CMOS technology. We have characterized the physical properties of the film using Auger, RBS and TEM analysis in the same range of temperatures, and find that as the annealing temperature is increased a better quality TiNxOy film is formed. The electromigration characteristics for Aℓ/TiNxOy/TiSi2 runners, as well as the role that this system plays in minimizing failures due to stress induced voiding are examined in this study.


1999 ◽  
Vol 595 ◽  
Author(s):  
S. J. Chung ◽  
O. H. Cha ◽  
H. K. Cho ◽  
M. S. Jeong ◽  
C-H. Hong ◽  
...  

AbstractThe defect levels associated with Mg impurity in p-type GaN films were systematically investigated in terms of doping concentration by photocurrent spectroscopy. Mg-doped GaN samples were grown on sapphire substrate by metal organic chemical vapor deposition and annealed in nitrogen atmosphere at 850 for 10 minutes. At room temperature, PC spectra showed two peaks at 3.31 and 3.15 eV associated with acceptor levels formed at 300 and 142 meV above valence band in as grown samples. But, after the thermal annealing, PC spectra exhibited various additional peaks depending on the Mg concentration. In the GaN samples with Mg concentration around 6 7 1017 cm−3, we have observed PC peaks related to Mg at 3.31 as well as 3.02 eV and carbon acceptor at 3.17 eV. For moderately Mg doped GaN samples, i.e., the hole concentration p=3 4 1017 cm−3, additional peak was observed at around 0.9 eV which can be attributed to defects related to Ga vacancy. For relatively low Mg doped samples whose hole concentrations are 1 2 1017 cm−3, additional broad peak was observed at around 1.3 eV. This peak may be related to the yellow band luminescence. As the Mg concentration is increased, the concentration of Ga vacancies can be reduced because Mg occupies the substitutional site of Ga in GaN lattice. When the hole concentration is above 6 7 1017 cm−3, the yellow luminescence and Ga vacancy related peaks disappeared completely.


Author(s):  
Takao Suzuki ◽  
Hossein Nuri

For future high density magneto-optical recording materials, a Bi-substituted garnet film ((BiDy)3(FeGa)5O12) is an attractive candidate since it has strong magneto-optic effect at short wavelengths less than 600 nm. The signal in read back performance at 500 nm using a garnet film can be an order of magnitude higher than a current rare earth-transition metal amorphous film. However, the granularity and surface roughness of such crystalline garnet films are the key to control for minimizing media noise.We have demonstrated a new technique to fabricate a garnet film which has much smaller grain size and smoother surfaces than those annealed in a conventional oven. This method employs a high ramp-up rate annealing (Γ = 50 ~ 100 C/s) in nitrogen atmosphere. Fig.1 shows a typical microstruture of a Bi-susbtituted garnet film deposited by r.f. sputtering and then subsequently crystallized by a rapid thermal annealing technique at Γ = 50 C/s at 650 °C for 2 min. The structure is a single phase of garnet, and a grain size is about 300A.


Author(s):  
H. Yen ◽  
E. P. Kvam ◽  
R. Bashir ◽  
S. Venkatesan ◽  
G. W. Neudeck

Polycrystalline silicon, when highly doped, is commonly used in microelectronics applications such as gates and interconnects. The packing density of integrated circuits can be enhanced by fabricating multilevel polycrystalline silicon films separated by insulating SiO2 layers. It has been found that device performance and electrical properties are strongly affected by the interface morphology between polycrystalline silicon and SiO2. As a thermal oxide layer is grown, the poly silicon is consumed, and there is a volume expansion of the oxide relative to the atomic silicon. Roughness at the poly silicon/thermal oxide interface can be severely deleterious due to stresses induced by the volume change during oxidation. Further, grain orientations and grain boundaries may alter oxidation kinetics, which will also affect roughness, and thus stress.Three groups of polycrystalline silicon films were deposited by LPCVD after growing thermal oxide on p-type wafers. The films were doped with phosphorus or arsenic by three different methods.


Author(s):  
Y. Kikuchi ◽  
N. Hashikawa ◽  
F. Uesugi ◽  
E. Wakai ◽  
K. Watanabe ◽  
...  

In order to measure the concentration of arsenic atoms in nanometer regions of arsenic doped silicon, the HOLZ analysis is carried out underthe exact [011] zone axis observation. In previous papers, it is revealed that the position of two bright lines in the outer SOLZ structures on the[011] zone axis is little influenced by the crystal thickness and the background intensity caused by inelastic scattering electrons, but is sensitive to the concentration of As atoms substitutbnal for Siatomic site.As the result, it becomes possible to determine the concentration of electrically activated As atoms in silicon within an observed area by means of the simple fitting between experimental result and dynamical simulatioan. In the present work, in order to investigate the distribution of electrically activated As in silicon, the outer HOLZ analysis is applied using a nanometer sized probe of TEM equipped with a FEG.Czodiralsld-gown<100>orientated p-type Si wafers with a resistivity of 10 Ώ cm are used for the experiments.TheAs+ implantation is performed at a dose of 5.0X1015cm-2at 25keV.


Author(s):  
P. Sadhukhan ◽  
J. B. Zimmerman

Rubber stocks, specially tires, are composed of natural rubber and synthetic polymers and also of several compounding ingredients, such as carbon black, silica, zinc oxide etc. These are generally mixed and vulcanized with additional curing agents, mainly organic in nature, to achieve certain “designing properties” including wear, traction, rolling resistance and handling of tires. Considerable importance is, therefore, attached both by the manufacturers and their competitors to be able to extract, identify and characterize various types of fillers and pigments. Several analytical procedures have been in use to extract, preferentially, these fillers and pigments and subsequently identify and characterize them under a transmission electron microscope.Rubber stocks and tire sections are subjected to heat under nitrogen atmosphere to 550°C for one hour and then cooled under nitrogen to remove polymers, leaving behind carbon black, silica and zinc oxide and 650°C to eliminate carbon blacks, leaving only silica and zinc oxide.


Author(s):  
Y. P. Lin ◽  
A. H. O’Reilly ◽  
J. E. Greedan ◽  
M. Post

In the basal planes of the orthorhombic YBa2Cu3O7-X compound with x=0.07, which has a Tc of around 90K, chains of copper-oxygen are formed along the [010] direction. Previous investigations on the variation of Tc with oxygen content have shown the existence of a plateau at Tc = 60K for x=0.3 to 0.4, suggesting the presence of a separate phase. This phase has also been identified to be orthorhombic, but with a 2x superlattice along [100] of the parent structure, and the superlattice has been attributed to the formation of alternating copper-oxygen and copper-vacancy chains. In our work, we have studied the chain ordering phenomenon by electron microscopy and neutron diffraction on samples with different oxygen contents. We report here some of our electron microscopy findings for samples with x=0.4.Powder samples of YBa2Cu3O7-X were prepared by controlled re-oxidation of previously reduced material. For electron microscopy, the sample was dry ground using a mortar and pestle in a dry nitrogen atmosphere without the use of any solvent and transferred dry onto holey carbon film for examination in a Philips CM12 microscope.


2019 ◽  
Vol 476 (21) ◽  
pp. 3281-3293 ◽  
Author(s):  
Elodie Lebredonchel ◽  
Marine Houdou ◽  
Hans-Heinrich Hoffmann ◽  
Kateryna Kondratska ◽  
Marie-Ange Krzewinski ◽  
...  

TMEM165 was highlighted in 2012 as the first member of the Uncharacterized Protein Family 0016 (UPF0016) related to human glycosylation diseases. Defects in TMEM165 are associated with strong Golgi glycosylation abnormalities. Our previous work has shown that TMEM165 rapidly degrades with supraphysiological manganese supplementation. In this paper, we establish a functional link between TMEM165 and SPCA1, the Golgi Ca2+/Mn2+ P-type ATPase pump. A nearly complete loss of TMEM165 was observed in SPCA1-deficient Hap1 cells. We demonstrate that TMEM165 was constitutively degraded in lysosomes in the absence of SPCA1. Complementation studies showed that TMEM165 abundance was directly dependent on SPCA1's function and more specifically its capacity to pump Mn2+ from the cytosol into the Golgi lumen. Among SPCA1 mutants that differentially impair Mn2+ and Ca2+ transport, only the Q747A mutant that favors Mn2+ pumping rescues the abundance and Golgi subcellular localization of TMEM165. Interestingly, the overexpression of SERCA2b also rescues the expression of TMEM165. Finally, this paper highlights that TMEM165 expression is linked to the function of SPCA1.


Sign in / Sign up

Export Citation Format

Share Document