Browsing by Author "Nhan Ai Tran"

Now showing 1 - 3 of 3

Controlled functionalization of a double-junction n(+)/n(-)/n(+) polysilicon nanobelt for hydrogen sensing application
(2016-04-01)
Nhan Ai Tran
;
Sang, Chen-Hsiang
;
Pan, Fu-Ming
;
Sheu, Jeng-Tzong
;
材料科學與工程學系奈米科技碩博班
In this paper, a double-junction n(+)/n(-)/n(+) polysilicon nanobelt selectively functionalized with platinum has been studied for hydrogen sensing application. The selective modification of the devices is performed by the combination of localized ablation of a resist and a lift-off process of e-beam evaporation of a catalyst material. The coverage of a Pt layer on the n(-) region is precisely controlled by adjusting Joule heating bias and pulse length. The Pt-functionalized devices show a rapid response to hydrogen with a limit of detection of only 5 ppm. The device with fully Pt-covered n(-) region is optimum for obtaining the best response to hydrogen. (C) 2016 The Japan Society of Applied Physics
Controlled functionalization of a double-junction n(+)/n(-)/n(+) polysilicon nanobelt for hydrogen sensing application
(2016-04)
Nhan Ai Tran
;
Sang, Chen-Hsiang
;
Pan, Fu-Ming
;
Sheu, Jeng-Tzong
;
材料科學與工程學系
In this paper, a double-junction n(+)/n(-)/n(+) polysilicon nanobelt selectively functionalized with platinum has been studied for hydrogen sensing application. The selective modification of the devices is performed by the combination of localized ablation of a resist and a lift-off process of e-beam evaporation of a catalyst material. The coverage of a Pt layer on the n(-) region is precisely controlled by adjusting Joule heating bias and pulse length. The Pt-functionalized devices show a rapid response to hydrogen with a limit of detection of only 5 ppm. The device with fully Pt-covered n(-) region is optimum for obtaining the best response to hydrogen. (C) 2016 The Japan Society of Applied Physics
Hydrogen gas sensors from polysilicon nanobelt devices selectively modified with sensing materials
(2016-12-16)
Nhan Ai Tran
;
Pan, Fu-Ming
;
Sheu, Jeng-Tzong
;
材料科學與工程學系
;
分子醫學與生物工程研究所
Double-junction n(+)/n(-)/n(+) polysilicon nanobelts featuring selectively deposited sensing materials have been investigated for application as H-2 gas sensors. The selective modification of the devices was performed through a combination of localized ablation of a resist and lift-off of a previous catalyst material deposited through e-beam evaporation. Four nanobelt devices, differentiated by their doping concentrations at the n(-) region (from 2.5. x. 10(13) to 2.5. x. 10(14) cm(-2)), were analyzed in terms of the responses to H-2 and their self-heating effects. A low doping concentration improved the response at room temperature, owing to a longer Debye length. The variation in the H-2-induced surface potential associated with temperature, accounting for degradation in the response of the nanobelts with Joule heating bias, was analyzed in terms of the I-V characteristics of the double-junction device. Among various catalysts (Pt, Pd, Pt/Pd) evaluated for their H-2 sensing characteristics, an ultrathin film of Pt/Pd was most favorable.