Charge transport in PbSe nanocrystal arrays

被引：100

作者：

Mentzel, T. S. ^{[1
]}

Porter, V. J. ^{[2
]}

Geyer, S. ^{[2
]}

MacLean, K. ^{[1
]}

Bawendi, M. G. ^{[2
]}

Kastner, M. A. ^{[1
]}

机构：

[1] MIT, Dept Phys, Cambridge, MA 02139 USA

[2] MIT, Dept Chem, Cambridge, MA 02139 USA

来源：

PHYSICAL REVIEW B | 2008年 / 77卷 / 07期

关键词：

D O I：

10.1103/PhysRevB.77.075316

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We report electrical transport measurements of arrays of PbSe nanocrystals forming the channels of field-effect transistors. We measure the current in these devices as a function of source-drain voltage, gate voltage, and temperature. Annealing is necessary to observe measurable current, after which a simple model of hopping between intrinsic localized states describes the transport properties of the nanocrystal solid. We find that the majority carriers are holes, which are thermally released from acceptor states. At low source-drain voltages, the activation energy for the conductivity is given by the energy required to generate holes plus the activation over barriers resulting from site disorder. At high source-drain voltages, the activation energy is given by the former only. The thermal activation energy of the zero-bias conductance indicates that the Fermi energy is close to the highest-occupied valence level, the 1S(h) state, and this is confirmed by field-effect measurements, which give a density of states of approximately 8 per nanocrystal as expected from the degeneracy of the 1S(h) state.

引用

页数：8

共 35 条

[1] Confinement effects in PbSe quantum wells and nanocrystals [J].