Fast Detection of Infrared Laser Pulses on Planar Small Area GaAs/AlGaAs Heterojunction

We report the first experimental observation of fast photovoltage in small area GaAs/AlGaAs heterojunction planar detector induced by nanosecond $CO_2$ laser pulses. This device revealed itself as a sensitive detector of millimeter waves and as a fast IR sensor operating at room temperature. Taking into account fast response of the detector and close to linear voltage-power dependence, the results are interpreted by photoemission of hot carriers over the potential barrier of the heterojunction.