By replacing the Al

x

Ga

1-x

As with [GaAs/AlAs] superlattice

a novel semiconductor/superlattice distributed Bragg reflector has been grown by molecular beam epitaxy system

at the same time the optical and electrical characteristics have also been measured. From the experimental results the center wavelength of the DBR reflection spectrum is about 850nm

the 19-period-DBR has the reflectivity as high as 99.5%

and the reflection bandwidth is as wide as 90nm. Moreover

using twice self-designed tungsten filament mask and proton implantation method we made the 15×15μm

2

square current flowing area to measure the series resistance of the p type DBR. This method avoided the difficulty in controlling the depth of implantation

and prevented the occurrence of side etching in wet chemical etching. The series resistance of the p type DBR is just about 50 Ohms. Therefore this kind of DBR has both a high reflectivity and low series resistance. Comparing with the normal semiconductor/semiconductor DBR

this kind of DBR can also simplify the structure design and fabrication of DBRs by omitting the modified heterointerface structures in the former DBR. It is clear that the simplification of the structure of DBRs can be a serious advantage in the VCSELs structure

therefore these factors reveal that this kind of DBR may have sufficient quality for the characteristics of VCSELs or the fabrication of the devices. Finally

the dependence of the series resistance of the DBR on temperature is also experimentally studied

from the result the series resistance depends on temperature slightly. It is clear that the thermal current depends more on temperature than the tunneling current

so the tunneling current should account for the majority of the current flowing in this kind of DBR

and it makes the DBR depend on temperature slightly. In VCSELs

the temperature characteristic is an important point in the performances of devices

so the characteristic of resistance depending on temperature slightly in this kind of DBR may improve the temperature characteristics of VCSELs with this kinds of DBRs.