SEMICONDUCTING MATERIALS

PROGRESS IS REPORTED ON METHODS OF PREPARING SINGLE AND POLYCRYSTALLINE SEMICONDUCTING COMPOUNDS SUCH AS CDTE, HGSE, BI2TE3, ZNTE, AND PBTE. A SERIES OF HOT PRESSED SPECIMENS WERE MADE TO STUDY THE VARIATIONOF PROPERTIES WITH GRAIN SURFACE AREA. VARIATION OF THE HOLDING TIMEAT CONSTANT TEMPERATURE FAILED TO PRODUCE THE DESIRED SPREAD OF GRAIN SIZES IN CDTE AND PBTE. SATISFACTORY SAMPLES OF HOT-PRESSES BP WERE PREPARED AT TEMPERATURES FROM 1670 TO2024 C AND SOME OF THEIR ACTIVATION ENERGIES ARE PRESENTED. THESE APPEAR TO BE A FUNCTION OF THE DEGREE OF SINTERING RATHER THAN OF PRESSURE OR TEMPERATURE. DIFFERENTIAL THERMAL ANALYSES DTA WERE MADE ON SAMPLES OF CDSE, HGTE, T1SE, CUL.4 TE, AND PTE2 PREPARED BY WET CHEMICAL TECHNIQUES. HOT PRESSING TEMPERATURES WERE SELECTED FROM THE DTA DATA AND 2 OR 3 SAMPLES OF EACH WERE PREPARED. THE HGTE, CRL.4TE., AND PTTE2 HAD LOW RESISTANCES. REFINEMENTS IN THE EQUIPMENT FOR MEASURING HALL COEFFICIENTS, PHOTOCONDUCTIVITY, AND PELTIER EFFECT ARE DESCRIBED.