<p> Abstract of paper for the International Conference on Semiconductor Physics & Devices, Guilin, China: November 20-22, 2015.</p><p>THE JOSHI EFFECT & THE N-P JUNCTION</p><p>Sanjay M Wagh</p><p>Central India Research Institute, 34, Farmland, Ramdaspeth, Nagpur 440010, India</p><p>Abstract:</p><p>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. </p><p>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. </p><p>[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.</p>