Atar Singh

Problem area inventory of parts of Hoshiarpur district through photo-interpretation

A systematic air-photo-interpretation procedure employing physiographic analysis has been used in preparing a quick inventory of the problem areas of parts of Hoshiarpur district of Punjab.The inventory has been prepared in respect of two selected areas viz. Hoshiarpur and Nangal on the basis of the study of photo-mosaic of Hoshiarpur district.The soil conservation needs of the predominant problem land units of both the areas are indicated.

Study of interfaces in organic semiconductor heterojunctions

The defect structure at the organic heterojunctions is studied using slow positron beam. The structural and electronic properties of heterojunctions are of technological and fundamental importance for understanding and optimization of electronic processes in organic devices. Interface trap centres play a significant role in the electrical conduction through the junctions. Depth dependent Doppler broadened annihilation measurements have been carried out in p- and n-type organic semiconductor thin films (30?80 nm) both single as well as multilayers grown on quartz substrate. The objective of the present study is to investigate the defect structure and to understand the behavior of positrons at the charged organic interfaces. Our result shows the sensitivity of positrons to the interfacial disorders that may be a convoluted effect of the presence of defects as well as the influence of the charge dipole in multilayers.