Mechanism of intersubband resonant photoresponse

We argue that the intersubband resonance observed in the dc conductivity of $p$-Si(100) MOSFET (metaloxide-semiconductor field-effect transistor) devices is a bolometric response and cannot properly be described as a photoconductivity effect. The process involves resonance heating of the electrons and a temperature-dependent channel conductivity. After a discussion of the electron-bolometer model, we present results on the sign, the magnitude, the source-drain voltage dependence, the density dependence, and the temperature and magnetic field dependences of the resonance signal.