LVI. Some Aspects of Peltier Heating at Liquid— Solid Interfaces in Germanium†

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Abstract
Peltier heating at a liquid-solid interface has unique advantages in controlling crystal growth processes in semiconductors and certain metals. The heat effect is produced at the interface without time-lag and can be reversed by reversing the current. Uses of Peltier heating in growing' single crystals, in producing n-p-n and n-p-n-p junctions in semiconductors, and in temperature gradient zone melting are discussed. The-velocity of interface movement due to Peltier heating permits an estimate of the Peltier coefficient P of a substance against its own liquid approximate values of 0-013 v for Bi and ∼ 0-2 v for Ge were obtained. The-direction of movement of a small molten alloyed region in a rod of solid Ge when a current is passed determines the sign of the Peltier coefficient-for solid Ge against the particular alloy. Such determinations on essentially intrinsic Ge, show P to be negative for alloys with Pt. Pd. Au, Ni: and positive for alloys with Ag, Al. Bi. Cu, Ga, Sn. Mg. Pb, Sb, and Te, where positive P signifies absorption of heat when current flows from solid to Liquid. The influence of Joule heating which accompanies Peltier-heating is assessed and means for avoiding its effect are discussed.