Alaa J. Ghazai

Performance enhancement of deep violet indium gallium nitride double quantum well lasers using delta barrier close to electron blocking layer

A thin aluminum gallium nitride (AlGaN) electron blocking layer (EBL), above the active region, is used to improve the performance and reduce threshold current of indium gallium nitride (InGaN) quantum well (QW) lasers. A new structure, with delta barrier close to EBL (AlGaN/0.3  nm GaN/InGaN), was devised to prevent deleterious polarization effects and confer other advantages. The effect of a 0.3 nm-thick GaN delta barrier on the performance of a deep violet InGaN double QW laser was investigated using ISE TCAD software. The results indicate that the delta barrier significantly enhances the output power, slope efficiency and external differential quantum efficiency while decreasing the threshold current.

Structural and Optical Properties of In0.27Ga0.73N/Si (111) Film Grown Using PA-MBE Technique

In this paper, InGaN/GaN/AlN/Si (111) structure was grown using a plasma-assisted molecular beam epitaxy (PA-MBE) technique. The structural and optical properties of grown film have been characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), high resolution X-ray diffraction (HR-XRD) and photoluminescence (PL). Indium-mole fraction has been computed to be 0.27 using XRD data and Vegards law with high grain size and low tensile strain. Room-temperature photoluminescence revealed an intense peak at 534 nm (2.3 eV) related to our sample In0.27Ga0.73N.

Effects of Cavity Length on Optical Characteristics of Deep Violet InGaN DQW Lasers

The performance characteristics and their dependence to cavity length of deep violet InGaN DQW lasers emitting at 390 nm have been investigated using the Integrated System Engineering Technical Computer Aided Design (ISE TCAD) software. The focus of simulation was on the study of optical properties which were carried out with varying cavity length from 200µm to 600µm. The simulation results indicated that the cavity length strongly affects the optical properties of the violet InGaN DQW laser. They showed that the parameters related to the output power such as optical intensity increases by increasing cavity length due to increase of applied current to the laser system. The results also indicated that the parameters such as optical material gain, stimulated and radiative recombination which are related to quantum efficiencies and laser performance decrease by increasing cavity length. It was shown that the laser structure with the longer cavity length has the lower optical loss.

The Influence of Geometrical Structure of AlInGaN Double Quantum Well (DQWs) UV Diode Laser on Its Performance and Operating Parameters

The development of efficient MQWs active regions of quaternary InAlGaN in the ultraviolet (UV) region is an engaging challenge by itself. Demonstrating lasers at such low wavelength will require resolving a number of materials, growth and device design issues. However, the quaternary AlInGaN represents a more versatile material since the bandgap and lattice constant can be independently varied. We report a quaternary AlInGaN double‐quantum wells (DQWs) UV laser diode (LDs) study by using the simulation program of Integrated System Engineering‐Technical Computer Aided Design (ISE TCAD). Advanced physical models of semiconductor properties were used. In this paper, the enhancement in the performance of AlInGaN laser diode can be achieved by optimizing the laser structure geometry design. The AlInGaN laser diodes operating parameters such as internal quantum efficiency ηi, internal loss αi and transparency threshold current density show effective improvements that contribute to a better performance.

Current–Voltage Characteristics of n-Al0.08In0.08Ga0.84N Schottky Diode Using Pt Metal Contact

In this study, current-voltage (I-V) measurements at room temperature (RT) of platinum (Pt) metal contact combine with n-Al0.08In0.08Ga0.84N thin film which grown epitaxially by molecular beam epitaxy (MBE) technique on sapphire substrate to form Schottky diode have been characterized. Schottky barrier heights of diode related with the high work function metal of Pt electrode was measured and investigated. Pt metal was fabricated using RF-sputtering technique. The effect of annealing temperature ranged from 300 °C to 600 °C on the structural and electrical properties has been studied. The results revealed that in spite of the various annealing temperature used there is no change in XRD diffraction peak observed in Pt contact. Furthermore, at 400 °C the best surface morphology was obtained and the value of SBH and ideality factor (n) was 0.76 eV and, 1.03 respectively. This concludes that at this annealing temperature Pt metal exhibited optimum (I-V) rectifying characteristics of Pt/Al0.08In0.08Ga0.84N Schottky diode.