MOVPE growth of GaP/GaPN core-shell nanowires: N incorporation, morphology and crystal structure

Dilute nitride III-V nanowires (NWs) possess great potential as building blocks in future optoelectronical and electrochemical devices. Here, we provide evidence for the growth of GaP/GaPN core-shell NWs via metalorganic vapor phase epitaxy, both on GaP(111)B and on GaP/Si (111) hetero-substrates. The NW morphology meets the common needs for use in applications, i.e. they are straight and vertically oriented to the substrate as well as homogeneous in length. Moreover, no parasitical island growth is observed. Nitrogen was found to be incorporated on group V sites as determined from transmission electron microscopy (TEM) and Raman spectroscopy. Together with the incorporation of N, the NWs exhibit strong photoluminescence in the visible range, which we attribute to radiative recombination at N-related deep states. Independently of the N incorporation, a peculiar facet formation was found, with {110} facets at the top and {112} at the bottom of the NWs. TEM reveals that this phenomenon is related to different stacking fault densities within the zinc blende structure, which lead to different effective surface energies for the bottom and the top of the NWs.This work was supported by the Deutsche Forschungsgemeinschaft (DFG, proj. no. HA 3096/4-2 & DA 396/6-2). We thank D Roßberg and D Flock for preparation of the TEM lamellae via FIB, as well as A Müller for technical support of the MOVPE system and W Dziony for AES measurements. We appreciate fruitful discussions with A Paszuk and A Nägelein

Grzybicze powiklania zakazen ukladu zastawkowego u dzieci z wodoglowiem wrodzonym

Mycotic complications of shunt infection in children with primary hydrocephalus. Recently, the incidence of fungal infections in children, including cbildren with shunt-dependent hydrocephalus, has increased. The analysis comprised 8 cbildren treated in the III Clinic of Pediatrics of ICZMP during the period of 12 months (12% of all infectious complications of the shunt system). The clinical picture of fungal infection included Symptoms of shunt dysfunction: febrile conditions, vomiting, distress and loss of appetite. The most common pathogens isolated from the cerebro-spinal fluid were fungi from the Candida species. Mean value of pleocytosis in the cerebro-spinal fluid was 812 cell/μ, and mean protein concentration was 311 mg/dl. Treatment consisted of monotherapy with Dillucan, monotherapy with Ancotil or combined treatment with Ancotil and Amphotericine B. The drugs were administered intravenously and intraventricolarly after removal of the shunt and application of external drainage. Sterility of cerebro-spinal fluid was obtained in the shortest time with the use of Ancotil. Propbylactic application of antifungal drugs decreases the frequency of infections in children with shunt-dependent hydrocepbalus

MOVPE growth of GaP GaPN core shell nanowires N incorporation, morphology and crystal structure

Dilute nitride III-V nanowires (NWs) possess great potential as building blocks in future optoelectronical and electrochemical devices. Here, we provide evidence for the growth of GaP/GaPN core-shell NWs via metalorganic vapor phase epitaxy, both on GaP(111)B and on GaP/Si (111) hetero-substrates. The NW morphology meets the common needs for use in applications, i.e. they are straight and vertically oriented to the substrate as well as homogeneous in length. Moreover, no parasitical island growth is observed. Nitrogen was found to be incorporated on group V sites as determined from transmission electron microscopy (TEM) and Raman spectroscopy. Together with the incorporation of N, the NWs exhibit strong photoluminescence in the visible range, which we attribute to radiative recombination at N-related deep states. Independently of the N incorporation, a peculiar facet formation was found, with {110} facets at the top and {112} at the bottom of the NWs. TEM reveals that this phenomenon is related to different stacking fault densities within the zinc blende structure, which lead to different effective surface energies for the bottom and the top of the NWs.This work was supported by the Deutsche Forschungsgemeinschaft (DFG, proj. no. HA 3096/4-2 & DA 396/6-2). We thank D Roßberg and D Flock for preparation of the TEM lamellae via FIB, as well as A Müller for technical support of the MOVPE system and W Dziony for AES measurements. We appreciate fruitful discussions with A Paszuk and A Nägelein

Structural and photoconducting properties of MBE and MOCVD grown III-nitride double-heterostructures

Investigations on standing wave (SW) interferometry come in focus of interest in the course of ongoing miniaturization of high precision length measurement systems. A key problem within these efforts is the development of a transparent ultra-thin photodetector for sampling the intensity profile of the generated SW. Group III-materials are promising candidates to ensure a good photodetector performance combined with the required optical transparency. In this work, we report on the interrelation of strain and dislocation density along with the influence of the structural properties on the sensitivity of double-heterostructure III-nitride photodetectors grown by molecular beam and metal organic vapour phase epitaxy

Sputtered ITO for application in thin-film silicon solar cells: Relationship between structural and electrical properties

Indium tin oxide (ITO) thin films for application in thin-film silicon solar cells with superior electrical and optical properties (resistivity ranging from 1.4 to 8.4x10-4 Ωcm; transparency of >80%) have been investigated. ITO layers were deposited by radio-frequency (RF) magnetron sputtering process at different argon gas pressures and substrate temperatures ranging from room temperature to 280°C. The main goal was to identify the relationship between structural and electrical properties. Generally, ITO layers were rather smooth with granular topography; electro-optically superior layers exhibited substantially different surface morphology of large, well-organized domain formations. Hall mobility of remarkably high value of 49 cm2/Vs (resistivity of 2.6x10-4 Ω.cm) was achieved for the ITO layers, which were deposited at surprisingly low temperature of 125°C. ITO deposition process has been successfully applied, even at room temperature, to fabricate front contacts for microcrystalline silicon solar cells, exhibiting excellent performance on both rigid and flexible substrates