14.2 Quantum Wires
405
(a)
(b)
Fig. 14.6 a Array of ZnO nanowhiskers on sapphire, fabricated using thermal evaporation. Adapted from [1353]. b
Single, free-standing ZnO nanowire fabricated using PLD. Adapted from [1354]
(a)
Au
InAs
InAs
InAs
InP
InP
(b)
Fig. 14.7 a TEM image of a part of an InAs whisker 40 nm in diameter that contains InP barriers. The zooms show
sharp interfaces. On top of the whisker is a gold droplet from the so-called vapor–liquid–solid growth mechanism. The
whisker axis is [001], the viewing direction is [110]. Adapted from [1348], reprinted with permission, ©2002 AIP. b
Subsequent growth stages of the tip of a GaAs nanowire with Au cap; times at which (in-situ) TEM image has been taken
are labelled. The arrows indicate the position of the growth front. Adapted from [1349], reprinted with permission,
©2018 APS
Such nanocrystals can also act as a nanolaser [1350, 1351]. In ZnO nanowhiskers the conversion
of mechanical energy into electrical energy has been demonstrated [1352] based on the piezoelectric
effect (Sect. 16.4).
The critical thickness h c in nanowire heterostructure is strongly modified from the 2D situation
(Sect. 5.4.1). Based on the strain distribution of a misfitted slab in a cylindrical wire [1355] the dependence of critical thickness on the nanowhisker radius r was developed [1356, 1357]. For given misfit
there is a critical radius r c for which h c is infinite for r < r c (Fig. 14.8).
405
(a)
(b)
Fig. 14.6 a Array of ZnO nanowhiskers on sapphire, fabricated using thermal evaporation. Adapted from [1353]. b
Single, free-standing ZnO nanowire fabricated using PLD. Adapted from [1354]
(a)
Au
InAs
InAs
InAs
InP
InP
(b)
Fig. 14.7 a TEM image of a part of an InAs whisker 40 nm in diameter that contains InP barriers. The zooms show
sharp interfaces. On top of the whisker is a gold droplet from the so-called vapor–liquid–solid growth mechanism. The
whisker axis is [001], the viewing direction is [110]. Adapted from [1348], reprinted with permission, ©2002 AIP. b
Subsequent growth stages of the tip of a GaAs nanowire with Au cap; times at which (in-situ) TEM image has been taken
are labelled. The arrows indicate the position of the growth front. Adapted from [1349], reprinted with permission,
©2018 APS
Such nanocrystals can also act as a nanolaser [1350, 1351]. In ZnO nanowhiskers the conversion
of mechanical energy into electrical energy has been demonstrated [1352] based on the piezoelectric
effect (Sect. 16.4).
The critical thickness h c in nanowire heterostructure is strongly modified from the 2D situation
(Sect. 5.4.1). Based on the strain distribution of a misfitted slab in a cylindrical wire [1355] the dependence of critical thickness on the nanowhisker radius r was developed [1356, 1357]. For given misfit
there is a critical radius r c for which h c is infinite for r < r c (Fig. 14.8).