Device with charge carrier injection for use in eg. light emitting laser sources - into wide band gap material via increasing band gap material

摘要

A device is claimed having an arrangement for charge carrier injection into large bandgap materials which are difficult to make conductive by doping comprising (a) a material with a constant or partially increasing narrow bandgap E1, forming a free charge carrier (electron or hole) source; (b) a material with a wide gap R3; (c) an undoped material with a bandgap insuedo-continuous increasing from E1 to E3; and (d) an arrangement for applying a voltage to cause charge carrier circulation from the narrow bandgap (E1) material towards the wide bandgap (E3) material via the increasing bandgap material. Also claimed are (i) a visible light-emitting laser source utilising the above device; (ii) an electroluminescent panel utilising the above device; (iii) a cold cathode utilising the above device; and (iv) a photocathode utilising the above device. USE/ADVANTAGE - Esp. for diode lasers emitting in the visible and esp. towards the short wavelengths (e.g. for high density information storage, submarine optical communication, etc.), but also for electroluminescent diodes (for optically controlled display devices), cold cathodes and photocathodes. High charge carrier concns. can be introduced into wide bandgap (esp. II-VI) semiconductors without the problems of heavy doning (auto-compensation phenomenon) and contact with the wide bandgap materials.