PMID- 25044675
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20150330
LR  - 20141121
IS  - 1613-6829 (Electronic)
IS  - 1613-6810 (Linking)
VI  - 10
IP  - 22
DP  - 2014 Nov
TI  - Effects of free carriers on piezoelectric nanogenerators and piezotronic devices 
      made of GaN nanowire arrays.
PG  - 4718-25
LID - 10.1002/smll.201400768 [doi]
AB  - This study investigates the role of carrier concentration in semiconducting 
      piezoelectric single-nanowire nanogenerators (SNWNGs) and piezotronic devices. 
      Unintentionally doped and Si-doped GaN nanowire arrays with various carrier 
      concentrations, ranging from 10(17) (unintentionally doped) to 10(19) cm(-3) 
      (heavily doped), are synthesized. For SNWNGs, the output current of individual 
      nanowires starts from a negligible level and rises to the maximum of  approximately 50 nA at a 
      doping concentration of 5.63 x 10(18) cm(-3) and then falls off with further 
      increase in carrier concentration, due to the competition between the reduction 
      of inner resistance and the screening effect on piezoelectric potential. For 
      piezotronic applications, the force sensitivity based on the change of the 
      Schottky barrier height works best for unintentionally doped nanowires, reaching 
      26.20 +/- 1.82 meV nN(-1) and then decreasing with carrier concentration. Although 
      both types of devices share the same Schottky diode, they involve different 
      characteristics in that the slope of the current-voltage characteristics governs 
      SNWNG devices, while the turn-on voltage determines piezotronic devices. It is 
      demonstrated that free carriers in piezotronic materials can influence the slope 
      and turn-on voltage of the diode characteristics concurrently when subjected to 
      strain. This work offers a design guideline for the optimum doping concentration 
      in semiconductors for obtaining the best performance in piezotronic devices and 
      SNWNGs.
CI  - (c) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
FAU - Wang, Chao-Hung
AU  - Wang CH
AD  - Department of Materials Science and Engineering, National Cheng Kung University, 
      Tainan, 70101, Taiwan.
FAU - Liao, Wei-Shun
AU  - Liao WS
FAU - Ku, Nai-Jen
AU  - Ku NJ
FAU - Li, Yi-Chang
AU  - Li YC
FAU - Chen, Yen-Chih
AU  - Chen YC
FAU - Tu, Li-Wei
AU  - Tu LW
FAU - Liu, Chuan-Pu
AU  - Liu CP
LA  - eng
PT  - Journal Article
DEP - 20140710
PL  - Germany
TA  - Small
JT  - Small (Weinheim an der Bergstrasse, Germany)
JID - 101235338
OTO - NOTNLM
OT  - GaN nanowire arrays
OT  - free carriers
OT  - piezoelectric nanogenerators
OT  - piezotronic devices
EDAT- 2014/07/22 06:00
MHDA- 2014/07/22 06:01
CRDT- 2014/07/22 06:00
PHST- 2014/03/21 00:00 [received]
PHST- 2014/05/19 00:00 [revised]
PHST- 2014/07/22 06:00 [entrez]
PHST- 2014/07/22 06:00 [pubmed]
PHST- 2014/07/22 06:01 [medline]
AID - 10.1002/smll.201400768 [doi]
PST - ppublish
SO  - Small. 2014 Nov;10(22):4718-25. doi: 10.1002/smll.201400768. Epub 2014 Jul 10.