Bulk crystal growth of Hg(1-x)Cd(x)Te for avalanche photodiode applications

The use of a solvent zone in the travelling heater zone growth method for high-bandgap Hg(1-x)Cd(x)Te, or 'MCT', crystals allows low temperatures and low mercury pressure to be employed over a large compositional range. In the case of the Cd-rich alloy range, the MCT material exhibits a large spin orbit coupling that results in a resonance effect; due to this resonance, the ionization coefficient of the hole is higher than that of the electron, resulting in a low excess noise factor in the avalanche photodiodes whose bandgap energy is close to the spin-orbit split.