(IMAGE) Osaka University Caption As shown in Figure a, in the neighborhood of the surface of semiconductor of GaN, the energy band is bent due to the surface potential. It is thought that photoexcited carriers are accelerated by the band bending, thereby radiating THz. It is also thought that the change in THz wave emission intensity due to defects, as shown in Figure b, is because the energy band bent significantly due to electrons trapped by defects near the surface, which further accelerated carriers. This shows that LTEM is effective for measuring the defect density of the surface of wide-gap semiconductors and their distribution of the surface potential. Credit Osaka University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.