A5087058940- Semiconductor Lasers and Optical Devices
- Semiconductor Quantum Structures and Devices
- Spectroscopy and Laser Applications
- Photonic and Optical Devices
- Solid State Laser Technologies
- Digital Radiography and Breast Imaging
- CCD and CMOS Imaging Sensors
- Optical Wireless Communication Technologies
- Thin-Film Transistor Technologies
- Medical Imaging Techniques and Applications
- Radiation Dose and Imaging
- Adaptive optics and wavefront sensing
- Photonic Crystals and Applications
- Advanced Fiber Optic Sensors
University of Surrey
2016-2021
National Physical Laboratory
2021
Schott (Germany)
2017
Technical University of Munich
2017
University of California, Santa Barbara
2017
Benue State University
2017
Abstract In this work we study the nature of band gap in GeSn alloys for use silicon-based lasers. Special attention is paid to Sn-induced mixing effects. We demonstrate from both experiment and ab-initio theory that (direct) Γ-character changes continuously with alloy composition has significant even at low (6%) Sn concentrations. The evolution due conduction effects, contrast sharp indirect-to-direct transition obtained conventional such as Al 1−x Ga x As. Understanding effects critical...
The efficiency limiting mechanisms in type-I GaInAsSb-based quantum well (QW) lasers, emitting at 2.3 µm, 2.6 µm and 2.9 are investigated.Temperature characterization techniques measurements under hydrostatic pressure identify an Auger process as the dominant non-radiative recombination mechanism these devices.The results supplemented with from three additional GaInAsSb extending wavelength range investigation 1.85-2.90μm.Under pressure, contributions CHCC CHSH to threshold current density...
In this paper, we discuss how the deliberate and controlled introduction of strain can be used to improve performance semiconductor lasers. We show strain-induced modifications electronic band structure give rise significant changes in valence III-V semiconductors which have been produce devices with lower threshold currents higher efficiencies. furthermore illustrate limit layers overcome by using compensation techniques is being widely adopted lasers based on a number emerging systems,...
From a systematic study of the threshold current density as function temperature and hydrostatic pressure, in conjunction with theoretical analysis gain carrier density, we have determined wavelength dependence Auger recombination coefficients InGaAsSb/GaSb quantum well lasers emitting 1.7-3.2 $\mu$m range. pressure measurements, non-radiative component currents for individual was continuously wavelength. The results are analysed to determine quantitatively. This procedure involves...
Abstract Type-II ‘W’-lasers have made an important contribution to the development of mid-infrared laser diodes. In this paper, we show that a similar approach can yield high performance lasers in optical communications wavelength range. (GaIn)As/Ga(AsSb) type-II ‘W’ structures emitting at 1255 nm been realised on GaAs substrate and exhibit low room temperature threshold current densities 200–300 A cm −2 , pulsed output powers exceeding 1 W for 100 µ m wide stripes, characteristic T 0 ≈ 90 K...
Abstract Although photovoltaic (PV) devices are rated at standard testing conditions (STCs), these STCs rarely met, either outdoors, or when PV used for indoor applications. Thus, it is beneficial to fully characterise the linearity of with respect irradiance. Moreover, high accuracy measurements essential reference cells (RCs), as they ensure precision measured This work presents a new technique based on digital light processing (DLP). The proposed system uses micromirror device coupled...
To harness the advanced fabrication capabilities and high yields of electronics industry for photonics, monolithic growth CMOS compatibility are required. One promising candidate which fulfils these conditions is GeSn. Introducing Sn lowers energy direct Γ valley relative to indirect L valley. The movement conduction band valleys with concentration critical design efficient devices; however, a large discrepancy exists in literature at GeSn becomes gap. We investigate bandgap character using...
To determine whether an activated or thresholdless Auger process dominants in mid-infrared lasers we investigated their variation with temperature and high-pressure. We found that below 2 μm the CHSH dominates. Above CHCC most readily explains experimental data.
Summary form only given. Semiconductor lasers operating in the 2-3 μm wavelength range are useful for a variety of applications including environmental monitoring, non-invasive medical diagnosis and industrial processing [1]. While type-I GalnAsSb/GaSb quantum well (QW) have achieved room temperature operation up to 3.73 μm, they limited by effects non-radiative Auger recombination, inter-valence band absorption carrier leakage due inadequate hole confinement, all which induce sensitivity...
We characterize the performance of 1.2 and 1.3 μm `W' lasers using temperature high-pressure. Both devices exhibit a high characteristic temperature. Pressure data indicates reduced influence Auger recombination compared to conventional type-I operating in same wavelength range.
Type-I quantum well (QW) lasers based on the GaSb material system show attractive characteristics in mid-infrared [1]. However, as wavelength (λ) increases range of 2–4 μm their performance begins to deteriorate due increasing Auger recombination [2]. In process, energy released from an electron-hole is transferred a third carrier. order develop strategies suppress recombination, it crucial understand magnitude and nature dominant pathway, dependencies operating λ temperature (T).
Type-II GaInAs/GaAsSb "W" quantum well heterostructures on GaAs show strong potential for temperature-stable data communications lasers. Devices emitting at 1255 nm promising lasing characteristics including room-temperature threshold current densities, Jth < 300 A/cm^2, pulsed output powers >1 W, and a reduced wavelength temperature dependence of 0.31 nm/C. Temperature- pressure-dependent characterisation techniques are used to determine the roles radiative non-radiative recombination....
Auger recombination is known to be a significant non-radiative process limiting near- and mid-infrared quantum well lasers. The one-dimensional confinement of wells small band offsets (relative the bandgap) permits two fundamentally different categories mechanisms operate. These may identified as either <i>activated</i> or <i>thresholdless</i> in nature. In this work, we investigate nature dominant mechanism emitting by characterizing range type-I InGaAsSb lasers operating within 2 - 3...
Auger recombination is known to be a significant non-radiative channel in near- and mid-infrared quantum well emitters [1] . As result, the threshold current density of semiconductor lasers increases substantially with increasing wavelength temperature, impacting overall efficiency laser-based optoelectronic system. In an process energy released from electron-hole transferred third carrier. The one-dimensional confinement wells small band offsets (relative bandgap) infrared type-I geometries...
Type-II (GaIn)As/Ga(AsSb) "W"-lasers offer the possibility to develop efficient and thermally stable near-infrared lasers. In this work, we investigate temperature- injection-dependent properties of operating between 1200-1260 nm use quantify influence radiative non-radiative recombination on device performance.