surface science ELSEVIER Surface Science 380 ( 1997 ) 293 301 Lattice-controlled electron transport characteristics in quantized surface layers at low temperature A.K. Ghorai, D.P. Bhattacharya * Department of Physics. Jadavpur University, Calcuna 700032, India Received 4 June 1996: accepted for publication 13 November 1996 Abstract A theory of intravalley acoustic scattering of the carriers in a non-degenerate two-dimensional electron gas is developed here under the condition of low lattice temperature when the assumptions of the well-known traditional theory are not valid. The scattering rates thus obtained are then used to estimate the zero-field mobility characteristics in an n-channel Si inversion layer. It is found that the finite energy of the phonons makes the energy and lattice temperature dependence of the scattering rate, and consequently the lattice temperature dependence of the mobility, significantly different from what follows, in the light of traditional theory which assumes equipartition law for the phonon distribution and neglects the phonon energy in comparison to the carrier energy. ~?, 1997 Elsevier Science B.V. Ke)'word,s: Electron solid interactions, scattering, diffraction; Electrical transport [conductivity, resistivity, mobility, ctc.l: Semiconductor insulator interfaces: Silicon I. Introduction The system of two-dimensional electron gas (2DEG) formed in semiconductor inversion and accumulation layers of metal-oxide-semiconduc- tor field-effect transistors (MOSFET) constitutes a part of the large class of dynamically two- dimensional systems. The study of the electrical transport properties of such a system has been largely motivated in recent years by its fundamen- tal physical importance on the one hand and possible device applications on the other [1-3]. Depending upon the lattice temperature TL and carrier concentration the electron transport in a 2DEG is controlled by various scattering mecha- nisms such as electron-lattice scattering, the *Corresponding author. scattering due to surface roughness and by the impurities near the oxide semiconductor interface. At lower temperatures the intravalley acoustic phonon and impurity scatterings dominate. The optical and intervalley phonon scatterings can be important only at high temperatures when an appreciable number of corresponding phonons is excited or in the presence of a high electric field when the non-equilibrium electrons can emit high- energy phonons. This apart, the non-planarity of the semiconductor interface gives rise to surface roughness scattering. Unlike others, the acoustic phonon scattering is an intrinsic process and the scattering involving intravalley acoustic phonons plays an important role in controlling the trans- port characteristics at low lattice temperatures (TL _<20 K) if the content of impurity atoms in the system under study is relatively low [ 1-20]. Some useful studies on the electrical transport 0039-6028/97/$17.00 Copyright (c) 1997 Elsevier Science B.V. All rights reserved PII S0039-6028 ( 96 )01578-6