TY - JOUR
T1 - High-performance hydrogen sensing properties and sensing mechanism in Pd-coated p-type Si nanowire arrays
AU - Baek, Jisun
AU - Jang, Byungjin
AU - Kim, Min Hyung
AU - Kim, Wonkung
AU - Kim, Jeongmin
AU - Rim, Hyun Jun
AU - Shin, Sera
AU - Lee, Taeyoon
AU - Cho, Sungmee
AU - Lee, Wooyoung
N1 - Publisher Copyright:
© 2017
PY - 2018/3
Y1 - 2018/3
N2 - We report on the H2 sensing performance and sensing mechanism in Pd-coated n- and p-type Si nanowire (NW) arrays, which were fabricated by an aqueous electroless etching method and sputtering. We found that the resistance of the Pd-coated n-type Si NWs decreased from the base resistance, whereas that of the p-type Si NW arrays increased, upon exposure to H2. The sensitivity (S = 1700% at 1% H2) of Pd-coated p-type NW arrays was much greater than that of the n-type NW arrays (S = 75%). Furthermore, we found that the dependency of the change in carrier density on H2 concentration was significantly greater in p-type Si NW arrays, while it was negligible in the n-type NW arrays. A Schottky barrier was formed between the Pd and n-Si (ϕM > ϕSC) before exposure to H2, which changed to an Ohmic contact (ϕM < ϕSC) after H2 exposure. In contrast, an Ohmic contact was formed between the Pd and p-Si (ϕM > ϕSC) before exposure to H2, which, after exposure, changed to a Schottky barrier (ϕM < ϕSC). Therefore, the p-type Si NW arrays were much more sensitive to H2 than the n-type Si NW arrays.
AB - We report on the H2 sensing performance and sensing mechanism in Pd-coated n- and p-type Si nanowire (NW) arrays, which were fabricated by an aqueous electroless etching method and sputtering. We found that the resistance of the Pd-coated n-type Si NWs decreased from the base resistance, whereas that of the p-type Si NW arrays increased, upon exposure to H2. The sensitivity (S = 1700% at 1% H2) of Pd-coated p-type NW arrays was much greater than that of the n-type NW arrays (S = 75%). Furthermore, we found that the dependency of the change in carrier density on H2 concentration was significantly greater in p-type Si NW arrays, while it was negligible in the n-type NW arrays. A Schottky barrier was formed between the Pd and n-Si (ϕM > ϕSC) before exposure to H2, which changed to an Ohmic contact (ϕM < ϕSC) after H2 exposure. In contrast, an Ohmic contact was formed between the Pd and p-Si (ϕM > ϕSC) before exposure to H2, which, after exposure, changed to a Schottky barrier (ϕM < ϕSC). Therefore, the p-type Si NW arrays were much more sensitive to H2 than the n-type Si NW arrays.
KW - Hydrogen gas sensor
KW - Pd
KW - Schottky/Ohmic contact
KW - Si nanowire arrays
UR - http://www.scopus.com/inward/record.url?scp=85032290994&partnerID=8YFLogxK
U2 - 10.1016/j.snb.2017.10.109
DO - 10.1016/j.snb.2017.10.109
M3 - Article
AN - SCOPUS:85032290994
SN - 0925-4005
VL - 256
SP - 465
EP - 471
JO - Sensors and Actuators, B: Chemical
JF - Sensors and Actuators, B: Chemical
ER -