SiC polytypes and doping nature effects on electrical properties of ZnO-SiC Schottky diodes, (2017), doi:10.1016/j.mee.2017 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.A C C E P T E D M A N U S C R I P T
ACCEPTED MANUSCRIPT
AbstractElectrical properties of ZnO/SiC Schottky diodes with two SiC polytypes and N and P doping are investigated. Characterization was performed through I-V and C-V-f measurements. Schottky barrier height (Φ b ), ideality factor (n), and series resistance (R s ) were extracted from forward I-V characteristics.(Φ b ), carrier's concentrations (N d -N a ) and (R s ) frequency dependence were extracted from C-V-f characteristics. The extracted n values suggest that current transport is dominated by interface generationrecombination and/or barrier tunneling mechanisms. When changing SiC polytypes, the rectifying ratio of ZnO/n-4HSiC is found to be twice that of ZnO/n-6HSiC. A change in doping nature gave a leakage current ratio of 40 between ZnO/p-4HSiC and ZnO/n-4HSiC. These results indicate that ZnO/p-4HSiC diodes have a complex current transport compared to diodes on n-type SiC. From I-V measurements, barrier height values are 0.63eV, 0.65eV and 0.71 eV for heterojunction grown on n-6HSiC, n-4HSiC and p-4HSiC, respectively. C-V measurements gave higher values indicating the importance of interface density of states. N ss values at 1MHz frequency are 4.54×10 11 eV -1 cm -2 , 3×10 12 eV -1 cm -2 and 8.13×1010 eV -1 cm -2 for ZnO/n-6HSiC, ZnO/n-4HSiC and ZnO/p-4HSiC, respectively. Results indicate the importance of SiC polytypes and its doping nature.
International audienceWith the expansion and the diversification of current networks in terms of applications, technologies and services, the network control and management are becoming overly hard to manage manually even for skilled administrators. The autonomic computing and the knowledge plane are two promising initiatives proposed to cope with the ever-growth network complexity. In this article, we propose to use the piloting plane concept to grant autonomicity in current networks. This plane aims at optimizing existing applications by using elaborate algorithms fed by pertinent knowledge recovered from the knowledge plane. In our approach, we demonstrate that the knowledge and the piloting planes are complementary and both are required when implementing autonomic solutions. We illustrate our proposal by applying these concepts on the handover selection phase which is a key issue in the handover process for granting global mobility to users in heterogeneous environment. We also describe a first implementation of our handover piloting system. Results from preliminary tests in real environments scenario exhibit the effectiveness of our system
This paper addresses handover decision instability which impacts negatively on both user perception and network performances. To this aim, a new technique called The HandOver Decision STAbility Technique (HODSTAT) is proposed for horizontal handover in Wireless Local Area Networks (WLAN) based on IEEE 802.11standard. HODSTAT is based on a hysteresis margin analysis that, combined with a utilitybased function, evaluates the need for the handover and determines if the handover is needed or avoided. Indeed, if a Mobile Terminal (MT) only transiently hands over to a better network, the gain from using this new network may be diminished by the handover overhead and short usage duration. The approach that we adopt throughout this article aims at reducing the minimum handover occurrence that leads to the interruption of network connectivity (this is due to the nature of handover in WLAN which is a break before make which causes additional delay and packet loss). To this end, MT rather performs a handover only if the connectivity of the current network is threatened or if the performance of a neighboringnetwork is really better comparing the current one with a hysteresis margin. This hysteresis should make a tradeoff between handover occurrence and the necessity to change the current network of attachment. Our extensive simulation results show that our proposed algorithm outperforms other decision stability approaches for handover decision algorithm.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.