Contact noise in n-type Hg1-xCdxTe photoconductors at 77 K

When gold wires are bonded to indium contacts on n-type Hg1-xCdxTe photoconductors with silver paste, the contacts are very noisy when carrying current. In all cases, the noisy contacts inject electrons into the sample when the contact acts as a cathode; in the poorest contacts, the noisy contact also injects holes when the polarity is reversed. The problem can be avoided by soldering the gold wires to the Hg1-xCdxTe samples with In solder or by bonding the gold wire to evaporated In contacts with the help of silver epoxy.