Dongmei Zeng a, Dong Guo b, Xu Ren a
a College of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, PR China
b Beijing Electronic Equipment Company limited, Beijing 100176, PR China
## Abstract
The polycrystalline CdZnTe films are promising material for fabrication of X-ray detection and solar cells. In this study, a pebble-like grain, hexagonal grain and worm-like grain of CdZnTe films were prepared via radio frequency magnetron sputtering. The morphology and properties of CdZnTe films were then characterized using atomic force microscopy, 2-D grazing-incidence wide-angle X-ray scattering, Raman spectra, transmission spectra and current–voltage curves. Accordingly, the CdZnTe crystal cell was found to be haphazardly arranged in the pebble-like grain, consequently demonstrating less anisotropy. In addition, the pebble-like grain film possessed a higher resistivity in light of the reduced anisotropy. In regard to the worm-like grain and hexagonal grain films, most CdZnTe (111) crystal planes were noted to be parallel to the sample surface. The worm-like grain film had the lowest absorption coefficient within the visible light range. Furthermore, the hexagonal grain film was shown to have the largest particle size, best crystallinity and lowest resistivity. The conductive mechanism of CdZnTe films of different morphologies was also discussed.
## Introduction
Cadmium Zinc Telluride (CdZnTe), a ternary alloy material, has garnered increased attention from its use in a wide range of applications, including X-ray or γ-ray particle radiation detection, nuclear spectroscopy, medical imaging and photo detection in light of its direct bandgap structure, high resistivity, high atomic number, high carrier mobility and adjustable gap [1], [2], [3], [4]. Compared to expensive and size limited bulk single crystals, CdZnTe films are advantageous due to their large-scale fabrication, which may be grown through radio frequency (RF) magnetron sputtering, vacuum thermal evaporation, close-spaced sublimation (CSS), and other techniques [5], [6], [7], [8].
CdZnTe films prepared by magnetron sputtering have good crystallization quality, good uniformity and a large area, which can be more appropriate for use in X-ray detection, UV photodetectors and solar cells [9], [10], [11], [12]. The performance of these devices is critically dependent on the morphology of the films and is very sensitive to both structure and its properties. However, further improvement in performance is limited as there is a lack in the fundamental understanding of the morphology (i.e., size, shape, texture, and phase distribution) of CdZnTe films.
In this study, the correlation between photoelectric properties and morphological features is summarized. In addition, the crystal orientation of CdZnTe films of various morphologies is studied by adopting synchrotron source grazing-incidence wide-angle X-ray scattering (GIWAXS) and atomic force microscopy (AFM) methods. Furthermore, the resistivity and conductive mechanism are shown to be dramatically affected by the morphology of CdZnTe films.
CdZnTe Association (CdZnTe.com)
https://www.cdznte.com/thesis/morphology-property-relationships-of-cdznte-films-prepared-via-radio-frequency-magnetron-sputtering.html