Abstract

For the study of blue light-emitting diodes(LEDs) using ZnS, from a prac tical point as well as a physical point of view, it is desirable to find out the prerequistie for making reproducible and reliable metal-partially compensated semiinsulating layer–semiconductor (MπS) structure. Since oxygen gives rise to acceptor-like levels which can result in an accumulated layer or a compensated layer being formed at the crystal surface, the application of compensated high-resistive layers due to oxidation might be useful for making an interposed π-layer between the metal electrode and low-resistive n-ZnS to obtain an efficient blue LED. Most recently, we have shown that the chemically oxidised π-layer consists of ZnO and ZnS mixed alloys¹⁾, and that the best diode records a room–temperature external quantum efficiency of about 8x10^-4 photons/electron and the halfwidth of about 65 nm at a drive voltage of 6 V for 15-20 mA.mm^-2 current densities. It is worth noting that these characteristics are superior to those in GaN and SiC²⁾ blue LEDs.

© 1984 Optical Society of America