[1]  J"unger A. On the existence and uniqueness of transient solutions of a degenerate nonlinear drift-diffusion model for
semiconductors. Math Models Methods Appl Sci, 1994, 4: 677--703

[2]  J"ungel A. Asymptotic analysis of a semiconductor model based on Fermi-Dirac statistics. Math Models Methods Appl Sci, 1996,
19: 401--424

[3]  Alabau F. A method for proving uniqueness theorems for the stationary semiconductor device and electrochemistry equations.
Nonlinear Analysis TMA, 1992, 18: 861--872

[4] Trioianiello G. Elliptic Differential Equations and Obstacle Problems. New York: Plenum Press, 1987

[5]  Jerome J W. Consistency of semiconductor modeling: an existence/stability analysis for the stationary van Roosbroeck system. SIAM J Appl Math, 1985, 45: 565--590

[6]  Fan Jishan,  Wu Hongwei. On the N-dimensional stationary drift-diffusion semiconductor equations. Nonlinear Analysis, 2001, 43: 127--135

[7] Lions J. Quelques Methodes de Resolutions des Problemes aux Limites non Lineaires. Paris: Dunod, 1969

[8] Ildefonso D'iaz J, Galiano G, J"ungel A. On a quasilinear degenerate system arising in semiconductors theory. Part I:Existence and uniqueness of solutions. Nonlinear Analysis: Real World Applications, 2001, 2: 305--336

[9] Ildefonso D\'{\i}az J,  Galiano G, J\"{u}ngel A. On a quasilinear degenerate system arising in semiconductors theory. Part
II: Localization of vacuum solutions. Nonlinear Anal, 1998, 36: 569--594

[10] Wang Y, Guan P. Periodic and stationary solutions of the semiconductor equations. Ann Math, 1998, 14: 262--274

[11] Guan P, Wu B. Existence of weak solutions to a degenerate time-dependent semiconductor equations with temperature effect. J
Math Anal Appl, 2007, 332: 367--380

[12] Paul R. Halbleiterphysik. Heidelberg: H"uthig-Verlag, 1975

[13]  Guo X, Li K. Asymptotic behavior of the drift-diffusion semiconductor equations. Acta Mathematica Scientia, 2004, 24B(3): 385--394

[14]  Wang Y, Fan J. On the existence uniqueness and regularity of steady state solutions to the basic semiconductor equations.
 Acta Mathematica Scientia, 1995, 15: 180--188