Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Highly sensitive hydrogen sensor based on graphite-InP or graphite-GaN Schottky barrier with electrophoretically deposited Pd nanoparticles Karel Zdansky | Zdansky Nanoscale Research Letters 2011 6 490 http content 6 1 490 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Highly sensitive hydrogen sensor based on graphite-InP or graphite-GaN Schottky barrier with electrophoretically deposited Pd nanoparticles Karel Zdansky Abstract Depositions on surfaces of semiconductor wafers of InP and GaN were performed from isooctane colloid solutions of palladium Pd nanoparticles NPs in AOT reverse micelles. Pd NPs in evaporated colloid and in layers deposited electrophoretically were monitored by SEM. Diodes were prepared by making Schottky contacts with colloidal graphite on semiconductor surfaces previously deposited with Pd NPs and ohmic contacts on blank surfaces. Forward and reverse current-voltage characteristics of the diodes showed high rectification ratio and high Schottky barrier heights giving evidence of very small Fermi level pinning. A large increase of current was observed after exposing diodes to flow of gas blend hydrogen in nitrogen. Current change ratio about 700 000 with hydrogen blend was achieved which is more than two orders-of-magnitude improvement over the best result reported previously. Hydrogen detection limit of the diodes was estimated at 1 ppm H2 N2. The diodes besides this extremely high sensitivity have been temporally stable and of inexpensive production. Relatively more expensive GaN diodes have potential for functionality at high temperatures. Keywords hydrogen sensor metal nanoparticles electrophoresis Schottky barrier InP GaN Introduction Hydrogen gas H2 monitoring sensors are in demand mainly for detection of H2 leakage in many industry productions such as H2 filling stations cryogenic cooling research labs etc. The gas is odorless colorless and highly inflammable and therefore effective H2 sensors are of great need for safety reasons. Highly sensitive and selective . exclusive to one gas H2 sensors are needed in forming gas leak
