Controllable etching and surface passivation of InP semiconductors are desirable for removing damaged surfaces and obtaining good electronic properties. We have observed that organic acids ~a-hydroxy acids: tartaric, lactic, citric, and malic!, when used in conjunction with HCl to etch the ~100! surface of InP results in smoother and defect-free surfaces, in comparison to etches based on inorga...

The effects of low-temperature annealing and oxidation of the dilute magnetic semiconductor Ga1−xMnxAs are studied by photoemission spectroscopy in the hard x-ray regime HAXPES , with special attention to the depth profile of both concentration and chemical state of manganese. Annealing of Ga1−xMnxAs in air at 190 °C for up to 150 h leads to an enrichment of manganese at the surface accompanied...

The feasibility of creating atomic wires on vicinal silicon surfaces via pseudomorphic step-edge decoration has been analyzed for the case of Ga on Si(112). Scanning tunneling microscopy and density functional theory calculations indicate the formation of Ga zigzag chains intersected by quasiperiodic vacancy lines or "misfit dislocations." This structure strikes a balance between the system's d...

The reduction in electronic recombination losses by the passivation of silicon surfaces is a critical enabler for high-efficiency solar cells. In 2006, aluminum oxide (Al2O3) nanolayers synthesized by atomic layer deposition (ALD) emerged as a novel solution for the passivation of pand n-type crystalline Si (c-Si) surfaces. Today, high efficiencies have been realized by the implementation of ul...

This paper presents a new method of passivation control by electroluminescence (EL) in 0.15 lm AlGaN/GaN HEMT. The electroluminescence signature in one finger HEMTs (W = 1 · 100 lm), and eight fingers ones (W = 8 · 125 lm), is modified by defects located at the passivation/semiconductor interface and is characterized by a light emission along the drain contact. This abnormal emission reveals so...

Growing high quality monolayer MoS2 with strong photoluminescence (PL) is essential to produce light-emitting devices on the atomic scale. In this study we show that rhombic monolayer MoS2 with PL intensity 8 times stronger than those of chemical vapour deposition (CVD)-grown triangular and mechanically exfoliated (ME) monolayer MoS2 can be prepared by using CVD. Both Raman and PL measurements ...

We have calculated formation energies and position of the defect levels for all native defects and for a variety of donor and acceptor impurities employing firstprinciples total-energy calculations. An analysis of the numerical results gives direct insight into defect concentrations and impurity solubilities as a function of growth parameters (temperature, chemical potentials) and into the mech...

Luminescent colloidal quantum dots (QDs) possess numerous advantages as fluorophores in biological applications. However, a principal challenge is how to retain the desirable optical properties of quantum dots in aqueous media while maintaining biocompatibility. Because QD photophysical properties are directly related to surface states, it is critical to control the surface chemistry that rende...

A simple method is developed to synthesize gram quantities of uniform Ge nanowires (GeNWs) by chemical vapor deposition on preformed, monodispersed seed particles loaded onto a high surface area silica support. Various chemical functionalization schemes are investigated to passivate the GeNW surfaces using alkanethiols and alkyl Grignard reactions. The stability of functionalization against oxi...

In this paper, passivity and passivation problems for event-triggered feedback interconnected systems are addressed. We consider passivity in two event-triggered control schemes based on the location of the event-triggered samplers: sampler at plant output and sampler at controller output. For both schemes, we first derive the conditions to characterize the level of passivity for the interconne...