Charge relaxation times Z. Insepov, V. Ivanov

Glass conductivity

Materials properties Pore structure Pore diameters – 20  m Al 2 O 3 +ZnO coatings – 1  m and 5  m Aspect ratio Materials parameters: Glass:  = 1  S/m,  =5.8 Al 2 O 3 +ZnO:  = 1  S/m,  =6.9 Air:  = 1  S/m,  =1

Al2O3 + ZnO coating resistivity h z r d r = 20  m d = 1  m h = 1.6 mm R 1 = N  R MCP resistance: R = M  N = 5  10 6 pores R 1 =R  N = ( M  )  5  10 6 = (90-500)  

Microscopic model of charge relaxation A.K. Jonscher, Principles of semiconductor device operations, Wiley (1960). A.H. Marshak, Proc. IEEE 72, (1984). A.G. Chynoweth, J. Appl. Phys. 31, (1960). R. Van Overstraeten, Solid St. Electronics 13 (1970) L.M. Biberman, Proc. IEEE 59, (1972). Z. Insepov et al, Phys.Rev. A (2008) r rr z r = 20  m  r = 1  m Aspect ratio 40 A. Spherical symmetry B. Cylindrical symmetry z r r = 1  m Al 2 O 3 D ,  ,N  – diffusion coeff., mobility, density of carriers (  = e,h)

ZnO/Al2O3 alloy relaxation times Channel Resistive Layer Material 30% Al2O3+70% ZnO Relaxation time (current setting) 6.1  sec Channel Resistive Layer Material 40% Al2O3+60% ZnO Relaxation time (desirable setting) 6.1  sec The current set of emissive coating parameters is not acceptable due to very high curent ~ 20 mA!

MCP Parameters Al2O3+ZnO Table 1: Dielectric constants [1] and resistivities [2] for Al2O3/ZnO ALD films *) DEZ -- Diethylzinc (Zn(CH2CH3) 1. Herrmann et al, Proc. of SPIE Vol (2005) p Elam et al, J. Electrochem. Soc. 150, pp. G339-G347, % DEZ* exposures Dielectric Constant Resistivity  (  cm) ~ x x Relaxation times, sec6x x Bulk MaterialBorosilicate glass Dielectric Const5.8 Conductivity 1  S/m Relaxation time 5.1  10 6 sec