Removal and Preparation of Electrodeposited Semiconductors for High Impedance Hall Effect Measurements

Abstract

The preparation of electrodeposited semiconductors for Hall effect measurements is complicated by the fact that these materials are, by necessity, attached to highly conducting substrates. As a result, methods were developed to reproducibly remove large area samples from their conducting substrates, and suitably prepared samples were used for temperature‐dependent Hall measurements and resistivity measurements. Apparatus was designed and built to routinely measure Hall voltages as low as 250 μV for source impedances up to 1012 Ω using films about 1 μm in thickness. Measurements were performed on numerous electrodeposited materials: normalCdTe , normalCdS , normalCdSe , and HgxCdfalse(1−xfalse)normalTe . Argon annealed electrodeposited normalCdTe was found to be consistently p‐type, with resistivity values typically 106–107 · Ω · cm p → n conversion of normalCdTe was achieved by diffusion of Cd at high temperature. HgxCdfalse(1−xfalse)normalTe was also p‐type, but had much lower resistivity and higher carrier concentration than normalCdTe . normalCdS and normalCdSe were both n‐type with carrier concentrations typically 1016 cm−3 and 1014–1016 cm−3, respectively.

Hall Effect and Resistivity Characterization of Doped, Electrodeposited CdSe

“…All films were annealed to 500~ in a nitrogen ambient. CdSe samples were prepared for electrical measurements by removal of part of the CdSe from the conductive ITO substrate with a nonshrink epoxy and a thermal shock (28). Five minutes epoxy was used as a base to mount the peeled CdSe and to embed small wire leads.…”

Hall effect measurements on CdTe layers electrodeposited from acidic aqueous electrolyte

“…A possible reason for there being few reports is that the sample preparation for Hall effect measurements is difficult because the conducting substrate must be removed from the electrodeposited layer, while the layer is maintained intact. In the present work, we employed a method in which the CdTe layer was transferred mechanically from the conducting substrate onto a non-conductive epoxy resin without the formation of cracks [11,12].…”

Electrical and optical properties of pulse plated CdS x Te1-x films

“…Then, the epoxy with the CdS x Te 1-x layer was removed from the substrate by tapping downward on the side of the ring with a mallet, in other words, by applying a shearing force between the CdS x Te 1-x layer and the substrate. In this way, crack-free CdS x Te 1-x layers on the non-conductive substrates could be obtained with high reproducibility [15,16]. The transferred CdS x Te 1-x layer was cut to a 6-mm square, and four indium electrodes with a diameter of 1.5 mm were deposited on each corner by vacuum evaporation through an aluminum foil mask.…”