This paper discusses the possibility of forming a photon avalanche in type-II heterostructures with deep quantum wells. The threshold IR light intensities that cause avalanche are hundreds of kilowatts per square centimeter. It is shown that a photon-avalanche mechanism can be used to generate nonequilibrium electron-hole pairs with weak IR light having a photon energy a factor of 3-5 less than the band gap of the semiconductor. The energy to switch the system between states with strong and weak absorption of the pump light ranges from a few to tens of picojoules per square micrometer.
E. Yu. Perlin, A. V. Ivanov, and R. S. Levitskii, "Cascade-avalanche up-conversion and generation of nonequilibrium electron-hole pairs in type-II heterostructures with deep quantum wells," J. Opt. Technol. 73, 9-17 (2006)