In situ Probe of GaN Film Surfaces under Plasma Conditions by Photoluminescence Technique

We have developed a method that enables us to in situ observe full photoluminescence (PL) spectra of n-type GaN film under plasma conditions. By subtracting background plasma noise from the total one, respectable luminescence of GaN film can be successfully obtained. After the plasma exposure, the near-band-edge emissions and yellow luminescence decrease but the blue luminescence intensity increases mainly due to the top surface damage of the GaN film. The results give us evidence that this in situ PL probe method can be potentially used for real-time damage monitoring of GaN film surfaces in plasma processes.