Improvement of device performance in UV-B laser diodes

Ultraviolet (UV) semiconductor lasers are widely used in medical and industrial applications, and their commercialization is strongly desired. Recently, laser oscillation by current injection in the UV-C and UV-B regions has been reported . From now on, it is necessary to demonstrate CW operation, which is indispensable for practical applications. In order to realize this, it is important to understand the internal loss and optical gain of the current devices. In this presentation, we report the details of our UV-B lasers. Specifically, we would like to discuss the results of the variable stripe length analysis of the internal loss of the obtained device and the performance of the UV-B lasers. The results show that the internal losses of the optimized UV-B laser are relatively low and good values are obtained. We also discuss the details of polarization doping, which is very effective in the realization of these UV lasers.