Oscar Vazquez-Mena

Learn More
The fabrication of gold nanodots by stencil lithography and its application for optical biosensing based on localized surface plasmon resonance are presented. Arrays of 50-200 nm wide nanodots with different spacing of 50-300 nm are fabricated without any resist, etching, or lift-off process. The dimensions and morphology of the nanodots were characterized(More)
This work reports on a considerable resolution improvement of micro/nanostencil lithography when applied on full-wafer scale by using compliant membranes to reduce gap-induced pattern blurring. Silicon nitride (SiN) membranes are mechanically decoupled from a rigid silicon (Si) frame by means of four compliant, protruding cantilevers. When pressing the(More)
In order to keep up with the advances in nano-fabrication, alternative, cost-efficient lithography techniques need to be implemented. Two of the most promising are nanoimprint lithography (NIL) and stencil lithography. We explore here the possibility of fabricating the stamp using stencil lithography, which has the potential for a cost reduction in some(More)
Several copy number-altered regions (CNAs) have been identified in the genome of cervical cancer, notably, amplifications of 3q and 5p. However, the contribution of copy-number alterations to cervical carcinogenesis is unresolved because genome-wide there exists a lack of correlation between copy-number alterations and gene expression. In this study, we(More)
Aluminum and gold nanowires were fabricated using 100 mm stencil wafers containing nanoslits fabricated with a focused ion beam. The stencils were aligned and the nanowires deposited on a substrate with predefined electrical pads. The morphology and resistivity of the wires were studied. Nanowires down to 70 nm wide and 5 mum long have been achieved showing(More)
The optical transparency and high electron mobility of graphene make it an attractive material for photovoltaics. We present a field-effect solar cell using graphene to form a tunable junction barrier with an Earth-abundant and low cost zinc phosphide (Zn3P2) thin-film light absorber. Adding a semitransparent top electrostatic gate allows for tuning of the(More)
A quantitative analysis of blurring and its dependence on the stencil-substrate gap and the deposition parameters in stencil lithography, a high resolution shadow mask technique, is presented. The blurring is manifested in two ways: first, the structure directly deposited on the substrate is larger than the stencil aperture due to geometrical factors, and(More)
Photovoltaics (PV) are a promising source of clean renewable energy, but current technologies face a cost-to-efficiency trade-off that has slowed widespread implementation. We have developed a PV architecture-screening-engineered field-effect photovoltaics (SFPV)-that in principle enables fabrication of low-cost, high efficiency PV from virtually any(More)
Active control of ion transport plays important roles in chemical and biological analytical processes. Nanofluidic systems hold the promise for such control through electrostatic interaction between ions and channel surfaces. Most existing experiments rely on planar geometry where the nanochannels are generally very long and shallow with large aspect(More)
The hydrogen sensing characteristics of a single nanotrench fabricated by focused ion beam milling (FIB) in an evaporated palladium microwire are presented. In situ atomic force microscopy (AFM) measurements proved that, in the presence of H(2), the trench closes and electrically connects the initially separated parts of the wire due to the increase in(More)