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197 results on '"Raja, M. Yasin"'

3. Investigation of VO?Zni?native donor complex in MBE grown bulk ZnO

Author

Asghar, M, Mahmood, K, Ferguson, IT, Raja, M Yasin A, Xie, YH, Tsu, R, and Hasan, M-A

Subjects
Condensed Matter Physics, Electrical and Electronic Engineering, Materials Engineering, Applied Physics
Abstract

In this paper, we have experimentally investigated the theoretical predictions of VO-Zni to be a native donor in ZnO. Intrinsically zinc-rich n-type ZnO thin films having ND ∼ 6.23 × 1018 cm-3 grown by molecular beam epitaxy on Si (0 0 1) substrate were annealed in oxygen environment at 500-800 °C, keeping a step of 100 °C for 1 h, each. Room temperature Hall measurements demonstrated that free donor (VO-Zni) concentration decreased exponentially and Arrhenius plot yielded activation energy to be 1.2 ± 0.01 eV. This value is in agreement with theoretically reported activation energy of VO-Zni donor complex in ZnO. We argue; this observation can be explained by two-step process: (i) incoming oxygen fills VO of VO-Zni complex leaving behind Zni; (ii) Zni releases its energy and moves to a lower energy state with respect to the conduction band minima and/or occupies an inactive location. Consequently, Zni-VO complex loses its donor role in the lattice. Our experimental data supported theoretical predictions of VO-Zni to be a native donor. Results from photoluminescence spectroscopy carried out on Zn-rich ZnO additionally justify the existence of VO-Zni complex. © 2013 IOP Publishing Ltd.

Published
2013

5. Simulation-Based Analytical Framework for M2M Autonomous Charging Infrastructure

Author

Bikmetov, Ravil, Lim, Churlzu, Bikmetova, Natalya, Kazi, Khurram, and Akhtar Raja, M. Yasin

Abstract

While a computerized simulation can be useful to gather user inputs during the new service development (NSD) process, it requires the active involvement of users/customers and can be costly and time-consuming compared to other practices such as surveys, focus groups, and interviews. However, when the service is rendered in the machine-to-machine (M2M) environment, the NSD process can exploit a simulation platform to assess service alternatives without customer involvement. This article contributes to the NSD research by identifying the services in the M2M environment as the suitable application area where a simulation platform can be effectively and efficiently implemented for data collection and analysis. We consider the autonomous charging service to demonstrate how a simulation-based analytical framework can help developing a new service in the M2M environment. As the electric vehicle (EV) industry has been evolving tremendously over the past decade, it becomes necessary to undertake significant modernization and autonomy adoption in the future charging infrastructure. Since the currently deployed charging infrastructure has not been designed to service autonomous EVs (AEVs) in an unsupervised manner, service plans to upgrade this infrastructure need to be developed to serve AEVs without any human intervention. Numerical experiments demonstrate how the simulation platform helps analyze autonomous charging station alternatives, provides recommendations for operational decisions, and creates a potential value for stakeholders and businesses during the NSD process.

Published
2023
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22. Holographic optical interconnects for VLSI multichip modules

Author

Feldman, Michael R., Morris, James E., Turlik, Iwona, Magill, Paul, Adema, Gretchen, and Raja, M. Yasin A.

Subjects
Very-large-scale integration -- Research, Holography -- Research, Complementary metal oxide semiconductors -- Research, Photodetectors -- Research, Business, Engineering and manufacturing industries, Science and technology
Abstract

A double pass holographic connection system, which is a prototype multichip model, lowers the switching energy and optical link latency for optically interconnected processor arrays. Silicon CMOS and GaAs laser array chips are attached to one side of the MCM substrate while etched computer generated holograms are present on the other side. These optical interconnects reduce the dissipated power.

Published
1994

27. Channel drop filters in woodpile-heterostructures.

Author

Zhifang Feng, Zhang, Dandan, and Akhtar Raja, M. Yasin

Subjects
HETEROSTRUCTURES, MICROWAVE filters, WAVEGUIDES, FINITE difference method, TIME-domain analysis, LATTICE constants
Abstract

Channel drop-filter is essential building blocks of transceivers that are the workhorse of Gbps communication and enable the emerging 100Gb/s technology. Using finite difference time domain method, heterostructures based channel drop filter in microwave region involving resonant system (in woodpile structure) are designed, analyzed, and simulated. Our simulations using hetero-woodpile-structures show that the resonant modes can be effectively adjusted in various ways, such as only changing the distance of two cavities or changing the lattice constants in the core woodpile. When bus/drop waveguides and resonant systems are located in different layers, we find that there is a resonant band [ABSTRACT FROM AUTHOR]

Published
2014
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