THz radiation from optically pumped n-type GaAs/InGaAs multi quantum well heterostructures

Spontaneous THz radiation from single and double‐quantum well GaAs/InGaAs heterostructures under CO2 laser pumping has been investigated. A spectral range of the emission from n‐type heterostructures was found to be within 90–100 μm (12–14 meV) for the maximum radiation intensity. A dependence of the luminescence signal from the samples on the pump intensity is linear up to 3 kW/cm2. A comparative analysis of the radiation from the heterostructures varying in the method of quantum well (QW) and barrier doping shows increasing of the spontaneous emission intensity with a growing concentration of impurity centres inside QW (deep QW in heterostructures with double QW), which is in agreement with theoretical estimations.