Novel semiconductor/superlattice distributed Bragg reflector (DBR) grown by molecular beam epitaxy (MBE) and its characteristics

Abstract

A novel semiconductor/superlattice AlAs/[GaAs/AlAs] DBR has been obtained through replacing the Al x Ga 1-x As in the AlAs/Al x Ga 1-x As DBR with GaAs/AlAs superlattice. In experiment, a p-type of this kind of 19-period DBR has been grown by V80H MBE system. From the experimental reflection spectrum, the central wavelength of the DBR is about 850nm and the 19-period DBR has the reflectivity high up to as 99.5%. Moreover, by using twice self-designed tungsten filament mask and proton implantation method, the 10 x 10 μ m 2 square current flowing area has been made to measure the series resistance of the p-type DBR. The method can solve the difficulty in controlling the depth of etching and prevent the occurrence of side etching in wet chemical etching usually used in experiments. From our experiment the series resistance of the DBR was just about 50 Ohms. Furthermore, the dependence of series resistance on temperature has also been studied. From the experimental results, it was found that the low series resistance of this kind of DBRs may be attributed to an increase in tunneling current on the semiconductor/superlattice minor structure that would lead to a decrease in the series resistance.