Surface-tunneling-induced 1/ f noise in Hg1−xCdxTe photodiodes

The reverse bias dark curent of Hg1−xCdxTe (MCT) photodiodes is often dominated by tunneling across a pinched off surface depletion region. The width of this critical region may be modulated by charge exchange with slow surface states in a passivant insulator. Numerical calculations give the correct order of magnitude for observed 1/ f noise in ZnS passivated MCT photodiodes.