Abstract: A novel method of using lasers for generating driving energy for activating P-type compound semiconductor films and reducing the resistivity thereof. The P-type compound semiconductor films are made from III-V nitrides or II-VI group compounds doped with P-type impurity. The present invention can be carried out in the ambience of atmosphere rather than in the ambience of nitrogen gas. In addition, adjusting the power and focusing distance of a laser source, and the power density can change the time required by the activating process.

Abstract: A novel method of using rapid variation of temperature for generating driving energy to activating P-type compound semiconductor films and reducing the resistivity thereof. The P-type compound semiconductor films are made from III-V nitrides or II-VI group compounds doped with P-type impurity. In addition, the time duration when the ambient temperature is greater than a certain temperature during the annealing process is limited to be less than one minute. Therefore, the optoelectronic performance of the P-type compound semiconductor films will not degrade because the duration of annealing process is decreased.

Abstract: A light-emitting device using a vacuum doughnut to serve as a current blocking layer is disclosed. The light-emitting device comprises: a substrate of a first conductivity type; a buffer layer formed on the substrate; a double heterostructure layer comprising a first cladding layer, an active layer and a second cladding layer, formed on the buffer layer; and a cap layer of a second conductivity type formed on the double heterostructure layer. A vacuum doughnut is formed between the active layer and an electrode formed on the cap layer to block a current flowing from the electrode formed on the cap layer so that the current flows through a region of the double heterostructure layer that is uncovered by the electrode. Furthermore, the vacuum doughnut can also be formed in the second cladding layer instead of forming in the cap layer.