The Diffusion of Nickel and Chlorine into P-Type Lead Telluride at 700°C

Abstract

The diffusion of nickel and of chlorine into single crystals of p-type lead telluride has been measured at 700~ When nickel and chlorine diffuse simultaneously, there is an interaction between them such that the concentration profile of the nickel exhibits a sharp minimum.

Highly Stable Metal─Na0.02Pb0.98Te Contacts for Medium Temperature Thermoelectric Devices

“…The EDS map shows that the Fe forms reaction layer-free contacts with SnTe, resulting in an interface with poor bonding. Such characteristics contradict the stable contact reported in this system prepared by a multistep process involving the melting and deposition of SnTe over Fe and then bonding with the p-type PbTe at 1081 K . The bonding occurs by intergranular penetration of the SnTe in Fe.…”

“…The spatial distribution of the various elements in SnTe and Na 0.02 Pb 0.98 Te indicates that the Co diffusion is The EDS map shows that the Fe forms reaction layer-free contacts with SnTe, resulting in an interface with poor bonding. Such characteristics contradict the stable contact reported in this system prepared by a multistep process involving the melting and deposition of SnTe over Fe and then bonding with the p-type PbTe at 1081 K. 34 The bonding occurs by intergranular penetration of the SnTe in Fe. The relatively low temperature of 923 K used in the hot pressing is in the solid-state zone, which seems to be inadequate for any notable metallurgical interaction between the Fe and SnTe.…”

“…% of Ni, indicating a substantial change in its composition during the hot-pressing. The diffusion length was calculated, based on the reported diffusion coefficient (10 –6 cm 2 sec –1 at 973 K) of Ni in PbTe, which indicates that the Ni can diffuse throughout the 3 mm thick TE material during hot pressing. However, the Ni/Na 0.015 Pb 0.985 Te contact prepared by a two-step consolidation and diffusion bonding in spark plasma sintering showed the formation of a stable 4.5 μm thick uniform pore free β 2 -Ni 3± x Te 2 phase .…”

Diffusion of Nickel and Chlorine into Lead Telluride

“…Both the nickel-63 and chlorine-36 were obtained as acid solutions (pH ~ 1) of NiC12 and contained 2.8 x 10 -2 mg Ni/ml. The tracer was applied to one face of the wafer as before (1) with one exception. It was found experimentally that if nickel-63 was deposited on the wafer by allowing an acid solution of 63NIC12 (pH 1) to evaporate to dryness on the surface of a wafer, instead of using a neutralized solutions (pH ~ 7), the diffusion results were identical with those in which nickel-63 was electroplated onto one surface.…”

“…The activity of the sources covered the range of count rates encountered here, and the standard sources were approximately the same size as the diffusion wafers. Each standard source was mounted in a stainless steel ring identical to those used for mounting the diffusion samples (1). From the relationships given by Libby (4,5), the linear absorption coefficient for the E-radiation of nickel-63 (Emax = 0.067 mev) in PbTe has been calculated as 18,700 cm -1.…”