2 results about "Surface states" patented technology

The application discloses a material structure for improving GaN heterojunction electron mobility and an epitaxial growth method thereof. The structure comprises, from bottom to top, a single crystal substrate, an AlN nucleation layer, a GaN buffer layer, an AlN insertion layer, a GaN isolation layer, a lower AlGaN barrier layer, an upper AlGaN barrier layer and an InGaN cap layer. The epitaxial growth method is characterized in that: the GaN isolation layer is introduced to suppress alloy disorder scattering; the lower barrier layer is grown by using a high V / III ratio low-speed process to reduce defects, and the upper barrier layer is grown by using a low V / III ratio high-speed process to improve the interface morphology; and finally, the InGaN cap layer is grown to relieve stress and reduce surface states. The application can synergistically suppress multiple scattering mechanisms, and the room temperature electron mobility is improved to 2270 cm 2 / V·s or above, and the surface roughness is significantly reduced, thereby providing a key material basis for high-performance GaN microwave devices.

The recording device selects cleaning control in response to the occurrence of an event. Therefore, it does not necessarily perform cleaning of the conveyor belt in accordance with the degree of contamination of the conveyor belt. [Solution] A recording device for recording on a recording medium, comprising: a recording means for performing the recording by ejecting ink onto the recording medium; a medium transport belt for transporting the recording medium on which the recording is performed by the recording means; a cleaning means that is movable to a contact position in contact with the medium transport belt or to a non-contact position not in contact with the medium transport belt, and performs a cleaning operation on the medium transport belt when located at the contact position; a discrimination unit for determining the surface state of the medium transport belt; and a control unit for causing the cleaning means to perform the cleaning operation according to the surface state of the medium transport belt determined by the discrimination unit.