Einstein Relation in Quantum Wires of Tetragonal Semiconductors
- PDF / 315,006 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 94 Downloads / 206 Views
EINST.EIN RZLATION IN QUANTUM WIRES OF TETRAGONAL SEDICONDUC TOR S KA1i-AKHYA P. GHATAK, 13.Di-*, M.MONDAL* AND S. N. BIS WAS* *Department of Electronics and Telecommunication 3nginee Ing, University of Jadavpur, Calcutta-700032, INDIA. *013 Little Brook Road, CT- o GS 2.O, DARI3N, Us S. A. ***Departnent of Physics, Y.S.Palpara College, P.O.Box. 721458, Midnapore, West Bengal, INDIA. ****Department of 3lectronics and Telecommunication "ngineering, B.E.College, Shibpur, Hovyrah-711103, West Bengal, I NDI A. ABSTRACT
"Wehave studied the Einstein relation for the diffusivity. mobility ratio (7PT) on the basis of a newly derived electron energy spectrum in Q74' of tetragonal semiconductors, within the framework of r.method by considering all types of anisotropies of the energy band parameters. It is found, taking n-Cd 3 As2 as an example that the DUTZ increases with electron concentration and decreases with film thickness in an oscillatory manner respectively. The theoretical results are in good aoreement with the suggested experimental method of determining the MIR in degenerate semiconductors having arbitrary dispersion law.
Wi'h remarkable developments in _ X:CVD and ot-her experimental techniques Z1l7, low-dimensional structures having quantum, confinement of two-dimensions such as quantum wires ( Q',Ws) have in the last few years attracted much attention not only for their potential in uncovering new phenomena in solid state science but also for their interestix, device applications 2,7. 2xtremely high mobility in Wjs 17, high perfor:-ciance of Q1.lasers * and modullators Z51 have been predicted. The potential use of these 1D synthetic materials for high speed devices makes the knowledge of their transport parameters desirable. We wvish to note that the D.,- for 4Ws of tetragonal semiconductors has yet to be r~eported though the D1•?
has extensively been studied for various types of materia-
ls under different physical conditions rc57 and the importance of studying the D.;',. has already been stated in f7.7. Tetragonal semiconductors are being extensively used as non-linear optical elements and light emitting diodes Z8'. In what follows. We shall investigate the DM, in "-.Wsof said semiconductors on the basis of the generalized electron dispersion laws as given elsewhere Z9.7. We shall study the electron concentration and thickness dependencas of the DIMR, taking n-C d3 As2 as an example. We shall also suggest an experimental method of determining the Dlv? in degenerate naterials having arbitrary disper sion laws.
Mat. Res. Soc. Symp. Proc. Vol. 198. @1990 Materials Research Society
334
The dispersion relation of the conduction electrons in bulk specimens of tetragonal semiconductors can be expressed
[Z97 as
Y7 + B (i1) pz2 + p+
C(E) =A(E) /-px
C)
where the notations are defined in the above reference. modified dispersion relation in QWs can be written as
(1A)
=
(2)
(n., ny, E)
k.
1(nxny, E)
where
The
2
/-C(E)-A(E)t2 t1 L (nx/2Lx)
2
+
-1/2
nyl/2Ly).7 1/2 /--B(E)7
The electron and the ot
Data Loading...
