An important purpose of science education is to help students acquire the ability to build appropriate model of systems. For facilitating such learning activity, modelbuilding learning environments (MBE) have been developed. Recent MBEs assist students in building conceptual models of systems and simulating their qualitative behavior. However, their feedback is insufficient when an erroneous mo...

Strained-layer superlattices (SLSs) are an active research topic in the molecular beam epitaxy (MBE) and infrared focal plane array communities. These structures undergo a >500 K temperature change between deposition and operation. As a result, the lattice constants of the substrate and superlattice are expected to change by approximately 0.3%, and at approximately the same rate. However, we pr...

A portable UHV molecular beam deposition system has been developed for synthesis, in situ, and real-time x-ray diffraction measurements of organic thin films, multilayers, and superlattices. The system has been optimized for small size, while still incorporating full features necessary to achieve thin film growth under molecular beam epitaxy ~MBE! conditions. It can be used independently for th...

This paper is concerned with the numerical simulations for the dynamics of the molecular beam epitaxy (MBE) model. The numerical simulations of the MBE models require long time computations, and therefore large time-stepping methods become necessary. In this work, we consider some unconditionally energy stable finite difference schemes, which will be used in the time adaptivity strategies. It i...

Self-organized growth of GaAs on (110) substrates vicinal to (111)A by hydrogen-assisted molecular beam epitaxy (H-MBE) has been studied for different kinetic regimes using atomic force microscopy (AFM). When GaAs growth is limited by kinetics of adatom incorporation to steps, the presence of chemisorbed H on the surface after oxide removal promotes the incorporation of adatoms to steps from th...

We report soft x-ray photoemission studies of metal/molecular-beam epitaxy (MBE)GaAs(lOO) interfaces formed at low temperature. Our results indicate that rectifying barrier heights are proportional to the metal work function in accordance with Schottky's original description of metal-semiconductor contacts. These results confirm the predictions of a selfconsistent model of metal-semiconductor i...

AlGaN/GaN high-electron-mobility transistors (HEMT) have been grown by radio frequency molecular beam epitaxy (RF-MBE) on 3” Si substrates. A record low contact resistance Rc ~ 0.11 .mm has been achieved for GaN HEMTs on Si by using non alloyed ohmic contacts regrown by MBE. Owing to the low contact resistance a 75-nm gate length unpassivated HEMT shows intrinsic current gain cut-off frequency ...

We present a fabrication technique and molecular beam epitaxy MBE regrowth of first-order, high contrast AlGaAs/GaAs diffraction gratings for laser emitting at 980 nm. An immersion holography technique is used to uniformly pattern first-order gratings with a pitch of 155 nm. MBE is used to overgrow Al0.75Ga0.25As on etched GaAs gratings. It is found that slow growth rates with optimum arsenic o...

We evaluate and compare two common methods, artificial neural networks (ANN) and support vector regression (SVR), for predicting energy productions from a solar photovoltaic (PV) system in Florida 15 min, 1 h and 24 h ahead of time. A hierarchical approach is proposed based on the machine learning algorithms tested. The production data used in this work corresponds to 15 min averaged power meas...