公开(公告)号：JPH10223377A

公开(公告)日：1998-08-21

申请号：JP1932398

申请日：1998-01-30

Applicant: IBM

Inventor： GUHA SUPRATIK ,  HAIGHT RICHARD ALAN ,  KARASINSKI JOSEPH M ,  TROUTMAN RONALD R

IPC: H01L51/50 ,  H01L51/52 ,  H05B33/12 ,  H05B33/14 ,  H05B33/22 ,  H05B33/26

Abstract: PROBLEM TO BE SOLVED: To provide an organic light emitting diode having a transparent cathode structure. SOLUTION: This structure has a metal thin film 64 having a low work function, and this metal thin film 64 is brought into direct contact with an electron transport layer 62 and is covered with a layer 66 of a broad band gap semiconductor. Since calcium has relatively high optical energy transmittance, and has the ability to form an electron injection contact having excellent properties for an organic substance, the metal forming the metal thin film 64 is preferably made of calcium. In addition, ZnSe, ZnS or their alloys exhibit excellent conductivity in a direction parallel to emission light, and has the ability to protect a low work function metal and an organic film in a lower layer, and is transparent for the emission light. Therefore, a semiconductor forming the semiconductor layer 66 is preferably selected from a group consisting of ZnSe, ZnS or their alloys.