ZnS blue light emitting device

• US 4,916,496 A
• Filed: 10/06/1988
• Issued: 04/10/1990
• Est. Priority Date: 01/27/1986
• Status: Expired due to Fees

• Current Assignee: Sharp Corporation (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Corporation (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kitagawa, Masahiko, Nakajima, Shigeo, Tomomura, Yoshitaka, Yamaue, Satoshi
• Primary Examiner(s): James, Andrew J.
• Assistant Examiner(s): Jackson, Jr., Jerome
• Application Number:
  US07/256,125
• Time in Patent Office: 551 Days
• Field of Search: 357/61, 357/17, 357/16
• US Class Current: 257/78
• CPC Class Codes: H01L 33/0037 having a MIS barrier layer
• CPC Class Codes: H01L 33/0083 for devices with an active region comprising only II-VI compounds

Abstract

An improved ZnS blue light emitting device is formed with a low-resistivity ZnS layer serving as a luminescent layer, a high-resistivity insulating layer of multi-layer structure for hole carrying injection above the low-resistivity ZnS layer and an electrode on the high-resistivity insulating layer. The high-resistivity insulating layer includes at least two stacked layers of different insulator materials serving different functions.

Claims

1. A ZnS blue light emitting device of metal-insulator-semiconductor structure comprising

a low-resistivity ZnS layer serving as a luminescent layer,

a high-resistivity insulating layer being formed on said low-resistivity ZnS layer and including two or more stacked layers of different insulating materials, said stacked layers including a first insulating layer adjacent said low-resistivity ZnS layer, said first insulating layer comprising a ZnO layer of thickness 50-200 Å

, and

an electrode formed on said high-resistivity insulating layer,

said high-resistivity insulating layer serving as an injection layer.

2. The device of claim 1 wherein said high-resistivity insulating layer is formed on a cleaved surface of said low-resistivity ZnS layer.

3. The device of claim 1 wherein said low-resistivity ZnS layer includes a monocrystalline ZnS pellet.

4. The device of claim 1 wherein said low-resistivity ZnS layer is epitaxially grown on a conductive substrate.

5. The device of claim 1 wherein said high-resistivity insulating layer includes two or more high-resistivity insulators selected from the group which consists of ZnS, ZnO, Al₂ O₃, SiO, SiO₂, Ta₂ O₅, ZrO₂, TiO₂, Nb₂ O₃, Y₂ O₃, BaO, BaS, CaS, CrS, B₂ O₃, B₂ S₃, LiF, KF, NaS, NaI, GaF₂, MgF₂, MnF₂, KCl, NaCl, KBr, NaBr, CaBr₂, CsI, Si₃ N₄, BeO, BeS, BeSe, BeTe, and their mixtures.

6. The device of claim 1 wherein said high-resistivity insulating layer has a total thickness of 5-100 nm.

7. The device of claim 1 wherein said electrode comprises vapor deposited Au.