The Joshi Effect of Electroluminescence in Solid Kno3

Abstract of paper for the International Conference on Semiconductor Physics & Devices, Guilin, China: November 20-22, 2015.

THE JOSHI EFFECT & THE N-P JUNCTION

Sanjay M Wagh

Central India Research Institute, 34, Farmland, Ramdaspeth, Nagpur 440010, India

Abstract:

The Joshi Effect, first observed [1, 2] in 1940, deals with the “reversible” influence of externally incident light on discharge glow in gases. In some cases, this influence is to ``quench or diminish’’ the discharge, leading to decrease of its glow. This is called as the negative Joshi effect. In some other cases, influence of externally incident light is to ``aid or enhance’’ the discharge, leading to an increase of its glow. This is called as the positive Joshi effect. We have recently shown [3] that the cylindrical geometry plays an important role in the controlling of such discharge characteristics. To begin with, we will briefly discuss few of these and related results.

Next, we will discuss the solid-state [4] analogue of the Joshi effect under cylindrical configuration. Specifically, we discuss cylindrical N-P junction whose thickness varies as the 1/ 3 cube-root of the voltage: d  (VJ Vext ) For cylindrical configuration, the electric field is maximum at the inner radius; and, under its conditions, dielectric breakdown occurs first at the inner radius. Control of the N-P junction properties, also via external illumination by light, is better for the considered cylindrical N-P junction than that of the properties of the planar junction; and is of definite importance for its applications, then.

[1] Joshi, S. S. and Narasinhan, V., A Light Effect in Chlorine under Electrical Discharge, Current Science, 1940, Vol. 9, 535-537 [2] See, also, the Appendix in Wagh, S. M. and Deshpande, D. A., Essentials of Physics, 2011, Vol. II, Prentice-Hall, New Delhi [3] Wagh, S. M. and Deshpande, D. A., Revisiting the Joshi Effect, Current Science, 10 November 2011, Vol. 101(9), 1182-1190. [4] Pankove, J. L., Optical processes in semiconductors, 1971, Prentice-Hall, New Jersey.