Modeling of diffusion motion of In nanoparticles in a CdTe crystal during laser-induced doping

S.M Levytskyi,A.V Stronski,Z Cao,T Zhao

doi:10.15330/pcss.22.2.301-306

Abstract

In order to solve the problem of the ohmic contact between the crystal surface and the metal electrode in the manufacturing process of the X/γ-ray detector, this paper uses a laser to probe the doping process of In/CdTe crystals in different media. In this experiment, the Traveling Heater Method (THM) is used to obtain CdTe(111) crystals that meet the requirements (ρ >109Ω∙cm). In and Au materials are respectively coated on the surface of the crystal sample by the vacuum thermal evaporation method to obtain the crystal sample meeting the requirements. The high-resistance p-type CdTe crystal of a relatively thick In film is irradiated with nanosecond laser pulses, the In film is used as an n-type doping source and as an electrode after laser irradiation.

Highlights

Cadmium telluride is an important group II-VI semiconductor material, and it has a direct transition band structure, the lattice constant is 0.6481 nm, the band gap is 1.5 eV, the electron mobility at room temperature is 1050 cm2/(V∙s), the hole mobility at room temperature is 80 cm2/(V∙s), the effective mass is 0.096
cadmium telluride (CdTe)(ZCd = 48, ZTe = 52)can be doped with various impurities to produce n-type or p-type semiconductor materials [1,2,3]
Highresistivity cadmium telluride (CdTe) semiconductor is a basic material for fabrication of high energy radiation direct-conversion detectors operating at room temperature and covering a wide energy range from a few keV to many MeV [1, 2]

Summary

Introduction

Cadmium telluride is an important group II-VI semiconductor material, and it has a direct transition band structure, the lattice constant is 0.6481 nm, the band gap is 1.5 eV, the electron mobility at room temperature is 1050 cm2/(V∙s), the hole mobility at room temperature is 80 cm2/(V∙s), the effective mass is 0.096. CdTe(ZCd = 48, ZTe = 52)can be doped with various impurities to produce n-type or p-type semiconductor materials [1,2,3]. The p-type CdTe crystal used in this experiment is doped with Cl element, and the resistivity is (> 109 Ω∙сm). CdTe has a very high light absorption coefficient (> 5×105/cm). A CdTe film with a thickness of only 2 μm has an optical absorption coefficient of more than 90% under standard conditions AM 1.5, and the highest theoretical conversion efficiency reaches 28 % [4]. Highresistivity cadmium telluride (CdTe) semiconductor is a basic material for fabrication of high energy radiation direct-conversion detectors operating at room temperature and covering a wide energy range from a few keV to many MeV [1, 2]

Objectives

Findings

Discussion

Conclusion