The sensitivity of graphene based devices to surface adsorbates and charge traps at the graphene/dielectric interface requires proper device passivation in order to operate them reproducibly under ambient conditions. Here we report on the use of atomic layer deposited aluminum oxide as passivation layer on graphene field effect devices (GFETs). We show that successful passivation produce hyster...

Ultra-thin AlN/GaN heterostructure field-effect transistors (HFETs) with, and without, SiN passivation were fabricated by the same growth and device processes. Based on the measured DC characteristics, including the capacitance-voltage (C-V) and output current-voltage (I-V) curves, the variation of electron mobility with gate bias was found to be quite different for devices with, and without, S...

Thermal atomic layer-deposited (ALD) aluminum oxide (Al2O3) acquires high negative fixed charge density (Qf) and sufficiently low interface trap density after annealing, which enables excellent surface passivation for crystalline silicon. Qf can be controlled by varying the annealing temperatures. In this study, the effect of the annealing temperature of thermal ALD Al2O3 films on p-type Czochr...

This chapter gives an overview of the theoretical bases of surface passivation and antireflection coating and describes the methods and equipment used to characterize the layers created in this work. While surface passivation is quantified by the effective surface recombination velocity Seff , this parameter cannot be measured directly. Instead, the lifetime measurements by QSSPC and ”PCD carri...

The impact of post-deposition hydrogen plasma treatment (HPT) on passivation in amorphous/crystalline silicon (a-Si:H/c-Si) interfaces is investigated. Combining low temperature a-Si:H deposition and HPT, a high effective charge carrier lifetime > 8ms is achieved on c-Si<100>, which serves as model for surfaces promoting epitaxy of a-Si:H. It is shown that the passivation improvement stems from...

The GaAs surface passivation effects of epitaxially grown ultra-thin GaP layers and surface As–P exchange have been investigated. Optical properties of passivated and unpassivated InGaAs/GaAs near-surface quantum wells (QWs) grown by metal organic vapor phase epitaxy (MOVPE) are studied by low-temperature continuous-wave and time-resolved photoluminescence (PL). By optimizing the growth conditi...

III/V semiconductor nanostructures have significant potential in device applications, but effective surface passivation is critical due to their large surface-to-volume ratio. For InP such passivation has proven particularly difficult, with substantial depassivation generally observed following dielectric deposition on InP surfaces. We present a novel approach based on passivation with a phosph...

The growth and surface passivation of near-surface InGaAs quantum wells (QWs) on GaAs (1 1 0) substrate have been investigated. Triangular shaped small islands, approximate areal density of 10 cm , are observed on metal organic vapor phase epitaxially grown GaAs single layer and InGaAs multi-quantum wells (MQWs) surfaces in a wide range of growth temperatures. By optimizing the growth condition...

Fast pyrolysis is a promising method for producing advanced biofuels and chemicals from lignocellulosic biomass. The process will however require further optimization to produce fuels and chemicals at a price competitive to conventional fossil fuel-derived products. Research in this dissertation focuses on both preand postprocesses for optimizing fast pyrolysis to produce increased yields of va...

A novel stack passivation scheme, in which plasma silicon nitride (SiN) is stacked on top of a rapid thennal SiO? (RTO) layer, is developed to attain a surface recombination velocity (S) approaching 10 em/s at the L3 O-cm p-typc (l00) silicon surfaee_ Such low S is achieved by the stack cven when the RTO and SiN films "I<ilvldllally yield considerably poorer surface passivation. Critical to ach...