| 摘要 |
1304593 Electroluminescence INTEL CORP 23 April 1970 [25 April 1969] 19629/70 Heading C4S [Also in Division H1] An ohmic contact to a layer of N type zinc sulphide, or a mixture thereof with another wide band gap material such as cadmium sulphide, consists of a layer including cadmium or zinc on a surface region having a net donor density of at least 10<SP>18</SP>/c.c. It is made by heating the cadmium or zinc in contact with the layer in the presence of a donor impurity which may be in the surface or incorporated in it during the heating. Suitable donors are indium, gallium, aluminium, chlorine, bromine and iodine. Typically an N type zinc sulphide body doped with 10<SP>19</SP> atoms/c.c. of aluminium (net donor concentration of 10<SP>17</SP>/c.c.) has its surface cleaved, abraded or etched for 5 minutes at 50‹ C. in hydrochloric acid, and then scrubbed with indium-mercury amalgam or gallium. Then a slug of a specified alloy of cadmium and indium; cadmium and gallium; or zinc and indium is pressed or evaporated on the prepared surface and heated in argon for 1 minute at 350-450‹C. In a similar process using a cadmium slug it is believed that cadmium fills lattice vacancies at the surface thereby increasing the net donor concentration. Heating can alternatively be effected in vacuum or in sulphur vapour. Reference is made to light emission and devices emitting light at a variety of wavelengths in a colour variable multicolour display. |
