GROWTH AND OPERATION OF A STEP-GRADED TERNARY III-V HETEROJUNCTION P-N DIODE PHOTODETECTOR

摘要

GROWTH AND OPERATION OF A STEP-GRADED TERNARY III-VHETEROJUNCTION P-N DIODE PHOTODETECTORAbstract of the DisclosureIn an infrared photodetection apparatus a photo-detector diode is used which comprises a heterojunction oftwo epitaxial layers of differing compositions of a ternaryIII-V semiconductive alloy, such that the outer layer willserve as a radiation-admitting window as well as physicalprotection for the underlying absorbing layer in the so-called direct photodetector diode configuration. Theternary alloy illustratively includes two metallic groupIII elements such as indium and gallium; but the principlecan be extended to ternary alloys including two group Velements, such as arsenic and antimony. Further, quaternaryalloys of III-V elements can be employed. The absorbinglayer is selected to be substantially intrinsic. Thelatter is the case for an n-type layer of InxGa(1-x)As.Matching of this absorbing layer to a gallium arsenidesubstrate is achieved by a plurality of step-graded composi-tion layers of indium gallium arsenide.- 1 -