Increased responsivity of photo-EMF detectors using asymmetric interdigitated contacts

Abstract

Summary form only given. Laser-based ultrasound detection uses photo-induced emf. The low responsivity of all conventional photo-emf sensors has been a serious challenge because it is more than an order of magnitude less sensitive than conventional photodetectors. The photo-emf sensor responsivity is improved via a novel surface electrode pattern: an asymmetric interdigitated contact (AIDC) geometry. Our design is shown with one pair and four pairs of interdigitated surface contacts. The single pair device is the conventional transverse-field photo-emf detector design, for above-bandgap operation.