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Article
Publication date: 15 February 2022

Tao Lin, Yaning Li, Rongjin Zhao, Zekun Ma and Jianan Xie

This paper aims to improve the device performance from the perspective of reducing ohmic contact resistance; the effects of different electrode structures and alloying parameters…

Abstract

Purpose

This paper aims to improve the device performance from the perspective of reducing ohmic contact resistance; the effects of different electrode structures and alloying parameters on the series resistance and power-current-voltage of laser diodes (LDs) have been investigated in this paper.

Design/methodology/approach

Four groups of p-GaAs side metal electrodes with different metal layer arrangements and thicknesses are fabricated for the investigated LDs. The investigated p-GaAs side electrodes are based on Ti/Pt/Au material and the n-GaAs side metal electrodes all have a same structure of Ni/Ge/Ni/Au/Ti/Pt/Au. The LDs with different electrodes were alloyed at 380°C for 60 s and 420°C for 80 s.

Findings

The experimental results show that the series resistance decreases by 14%–20%, the output power increases by 2%–2.2% and the conversion efficiency increases by 1.69%–2.16% for the LDs prepared with optimized alloying parameters (420°C for 80 s). The laser diode with p-GaAs side Ti/Pt/Au electrode of 30/70/100 nm has the best device characteristics under both annealing conditions.

Originality/value

The utilization of this improvement on ohmic contact property in electrode is not only very important for upgrading high-power LDs but also helpful for GaAs-based microelectronic devices such as HBT and monolithic microwave integrated circuit.

Details

Circuit World, vol. 49 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 7 December 2020

Joy Chowdhury, Angsuman Sarkar, Kamalakanta Mahapatra and Jitendra Kumar Das

The purpose of this paper is to present an improved model based on center potential instead of surface potential which is physically more relevant and accurate. Also, additional…

Abstract

Purpose

The purpose of this paper is to present an improved model based on center potential instead of surface potential which is physically more relevant and accurate. Also, additional analytic insights have been provided to make the model independent and robust so that it can be extended to a full range compact model.

Design/methodology/approach

The design methodology used is center potential based analytical modeling using Psuedo-2D Poisson equation, with ingeniously developed boundary conditions, which help achieve reasonably accurate results. Also, the depletion width calculation has been suitably remodeled, to account for proper physical insights and accuracy.

Findings

The proposed model has considerable accuracy and is able to correctly predict most of the physical phenomena occurring inside the broken gate Tunnel FET structure. Also, a good match has been observed between the modeled data and the simulation results. Ion/Iambipolar ratio of 10^(−8) has been achieved which is quintessential for low power SOCs.

Originality/value

The modeling approach used is different from the previously used techniques and uses indigenous boundary conditions. Also, the current model developed has been significantly altered, using very simple but intuitive technique instead of complex mathematical approach.

Details

Circuit World, vol. 50 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 6 December 2023

Xiaolong Lu, Xudong Sui, Xiao Zhang, Zhen Yan and Junying Hao

This study aims to investigate the effect of V doping on the microstructure, chemical stability, mechanical and vacuum tribological behavior of sputtered MoS2 coatings.

Abstract

Purpose

This study aims to investigate the effect of V doping on the microstructure, chemical stability, mechanical and vacuum tribological behavior of sputtered MoS2 coatings.

Design/methodology/approach

The MoS2-V coatings are fabricated via tuning V target current by magnetron sputtering technique. The structural characteristic and elemental content of the coatings are measured by field emission scanning electron microscopy, X-ray diffractometer, electron probe X-ray micro-analyzer, Raman, X-ray photoelectron spectroscopy, high resolution transmission electron microscope and energy dispersive spectrometer. The hardness of the deposited coatings are tested by a nanoindentation technique. The vacuum tribological properties of MoS2-V coatings are studied by a ball-on-disc tribometer.

Findings

Introducing V into the MoS2 coatings results in a more compact microstructure. The hardness of the coatings increases with the doping of V. The MoS2-V coating deposited at a current of 0.2 A obtains the lowest friction coefficient (0.043) under vacuum. As the amount of V doping increases, the wear rate of the coating decreases first and then increases, among which the coating deposited at a current of 0.5 A has the lowest wear rate of 2.2 × 10–6 mm3/N·m.

Originality/value

This work elucidates the role of V doping on the lubrication mechanism of MoS2 coatings in a vacuum environment, and the MoS2-V coating is expected to be applied as a solid lubricant in space environment.

Details

Industrial Lubrication and Tribology, vol. 76 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

Open Access
Article
Publication date: 10 July 2023

Moses Muhwezi, Henry Mutebi, Samuel Ssekajja Mayanja, Benjamin Tukamuhabwa, Sheila Namagembe and Robert Kalema

Procuring relief products and services is a challenging process for humanitarian organizations (HOs), yet it accounts for approximately 65% of relief operations’ costs (Moshtari…

1750

Abstract

Purpose

Procuring relief products and services is a challenging process for humanitarian organizations (HOs), yet it accounts for approximately 65% of relief operations’ costs (Moshtari et al., 2021). This paper aims to examine how procurement internal controls, materials and purchasing procedure standardization influence information integration and procurement performance.

Design/methodology/approach

In this study, partial least square structural equation models and multigroup analysis were used to analyze data collected from 170 HOs.

Findings

Procurement internal controls and material and purchasing procedure standardization fully mediate between information integration and procurement performance.

Research limitations/implications

The study focuses only on HOs. Since humanitarian procurement projects take place over a period of several years, it is difficult to capture the long-term effects of information integration, procurement internal controls, material and purchasing procedure standardization and procurement performance. In this regard, a longitudinal study could be undertaken, provided that the required resources are available.

Practical implications

Procurement managers should implement information integration practices within acceptable procurement internal controls and standardize material and purchasing procedures to boost procurement performance.

Originality/value

By integrating information through procurement internal controls and standardizing material and purchasing procedures, procurement performance in a humanitarian setting can be systematically optimized.

Details

Journal of Humanitarian Logistics and Supply Chain Management, vol. 13 no. 4
Type: Research Article
ISSN: 2042-6747

Keywords

Article
Publication date: 1 March 2023

Yuzhen Zhao, Mingxu Zhao, Huimin Zhang, Xiangrong Zhao, Yang Zhao, Zhun Guo, Jianjing Gao, Cheng Ma and Yongming Zhang

This paper aims to prepare third-order nonlinear optical (NLO) organic materials with large nonlinear optimization value, high damage threshold and ultrafast response time.

Abstract

Purpose

This paper aims to prepare third-order nonlinear optical (NLO) organic materials with large nonlinear optimization value, high damage threshold and ultrafast response time.

Design/methodology/approach

A series of novel symmetric and asymmetric compounds possessing third-order NLO properties were synthesized using 1,3,5-tribromobenzene as the basis. The photophysical and electrochemical properties, as well as the click reactions, were characterized by means of UV–VIS–NIR absorption spectroscopy and cyclic voltammetry.

Findings

The donor–acceptor chromophores were inserted into compound, making the molecule to have a broader absorption in the near-infrared regions and a narrower optical and electrochemical band gap. It also formed an electron-delocalized organic system, which has larger effects on achieving a third-order NLO response. The third-order NLO phenomenon of benzene ring complexes was experimentally studied at 532 nm using Z-scan technology, and some compounds showed the expected NLO properties.

Originality/value

The click products exhibit more NLO phenomena by performing different click combinations to the side groups, opening new perspectives on using the system in a variety of photoelectric applications.

Details

Pigment & Resin Technology, vol. 53 no. 3
Type: Research Article
ISSN: 0369-9420

Keywords

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