Academic journal article American Academic & Scholarly Research Journal

Optimized High Performance Characteristics of a Designed 420nm InGaN/AlGaN MQW Blue Violet Laser

Academic journal article American Academic & Scholarly Research Journal

Optimized High Performance Characteristics of a Designed 420nm InGaN/AlGaN MQW Blue Violet Laser

Article excerpt

Abstract: In this work, the performance characteristics of a designed 420nm multi quantum well (MQW) Blue Violet Laser using InGaN/AlGaN materials are presented. A high performance of the designed laser is obtained with the optimized values of injection current and differential gain. A maximum optical output power of 214.45mW is obtained for 87mA injection current and 1x10^sup -16^cm^sup 2^ differential gain, where, the threshold current is 8.7mA. The modal gain of 74.155 cm^sup -1^ and the differential quantum efficiency of 67.02% are obtained. A maximum resonance frequency of 7.9675GHz and the corresponding modulation bandwidth of 10.75 GHz are obtained for the same values of injection current and differential gain. The performance of the laser is also analyzed by varying injection current and differential gain. A maximum output power of 214.45mW is obtained for 117mA injection current and 4x10^sup - 16^cm^sup 2^ differential gain of. For this, a maximum resonance frequency of 18.742 GHz and the corresponding modulation bandwidth of 25 GHz are obtained which enhances the dynamic performance of the designed laser for applications in data storage, optical discs and displays.

Keywords: Output Power, Resonance Frequency, Modulation Bandwidth, MQW, Blue Violet Laser

(ProQuest: ... denotes formulae omitted.)

1. INTRODUCTION

Semiconductor laser diodes have applications in the field of data storage, printing, optical communications, spectroscopy etc. due to their small size, low power dissipation and high quantum efficiency. The laser diodes can be designed for different emission wavelengths based on applications. High resolution laser color printers and low cost full color projection systems could be designed by moving towards shorter wavelength laser diodes. The density and at the same time resolution can be improved by a reduction in emission wavelength of the laser diode. Infra-red laser diodes which are being affordable prices are being widely used.

Nitride materials are stable at high temperatures and also chemically stable. GaN material has been chosen for the emission in shorter wavelength because this material has a wide band gap and sufficient to emit light in the ultraviolet region (Lee et al. 2010), (Kuchibhatla 2005), (Kehl Sink 2000). The band gap of this material could be varied by forming alloys with other materials. It has higher quantum efficiency and longer life time although it has a high defect density. GaN material can be alloyed with other materials like InN and AlN to obtain a range of emission wavelengths which is possible with the variation of the Indium and Aluminium concentrations. Analysis of InGaN material characteristics is required for deep UV laser diodes which have applications in biosensing such as detecting chemical agents.

The active layer of the Nichia devices was formed by InGaN quantum wells. This new invention enabled the development of small, convenient and low-priced blue violet laser and opened the way for applications such as high-density HD DVD data storage, Blue-ray discs, Micro projectors and displays (Brüninghoffet al. 2009), (Skierbiszewski et al. 2011), (Holc et al. 2012), (Strau et al. 2008), (Lonsdale et al. 2002).

In this work, the optimization of a designed 420nm InGaN/AlGaN based MQW Blue Violet Laser is presented with the aim of obtaining high performance characteristics.

2. DEVICE STRUCTURE

The active region of a Blue Violet semiconductor laser, presented in fig. 1, consisting 3 QWs of In0.12Ga0.88N (bandgap energy, Eg=2.9566eV; refractive index, n=2.6147; effective mass of electron in the conduction band, mc=0.18443m0; effective mass of hole in the valence band, mv=0.293568m0; where, m0 is the mass of electron) of 5nm each and 2 barriers of Al0.15Ga0.85N (Eg=3.683eV, n=2.44) of 7 nm each. The concentrations of the materials are selected for achieving the operating wavelength of the device of nearly 420nm (Adachi 2005), (Vurgaftman et al. …

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