Cadmium zinc telluride: a new material for solar cells

Cadmium zinc telluride material introduction

Cadmium zinc telluride, also called CdZnTe, abbreviated as CZT. CZT crystal is a wide band gap II-VI compound semiconductor, which can be regarded as solid solution of CdTe and ZnTe. The melting point varies between 1092 and 1295 degrees Celsius depending on the amount of Zn added. CZT crystals are widely used as epitaxial substrates for infrared detectors HgCdTe and room temperature nuclear radiation detectors. CdZnTe crystal is a functional material with great engineering and strategic significance. For example, a medical imager made of CdZnTe can take clearer pictures when examining the body of a patient, and at the same time, it can reduce radiation. CdZnTe crystal is also an important raw material for the manufacture of instruments and meters with excellent performance.

Cadmium telluride application areas

It is also widely used as the epitaxial substrate of infrared detector HgCdTe and room temperature nuclear radiation detector, etc. It has excellent optoelectronic properties and can directly convert X-rays and γ-rays into electrons at room temperature. The most ideal semiconductor material for making room temperature X-ray and γ-ray detectors. Compared with silicon and germanium detectors, CdZnTe crystals are the only semiconductors that can operate at room temperature and can handle two million photons/(s·mm). In addition, CdZnTe crystals have better spectral power than all commercially available beamsplitters. The many advantages of the CdZnTe detector make it more and more widely used in nuclear safety, environmental monitoring, astrophysics and other fields. In scientific research, the CdZnTe detector has great application prospects in high-energy physics, for example, it can be used in the acceleration system of high-energy particles. Compound semiconductor detectors are highly competitive, and applications in particle physics are expected to be greatly developed. In addition, CdZnTe detectors also have broad application prospects in astrophysical research. At present, the research of CdZnTe detector is a very meaningful new subject in a rapid development stage.

Cadmium telluride powder historical research

Research on CdZnTe material first started in 1991, and has caused a stir in the industry due to its high-resolution potential and remarkable property that it can operate at room temperature. But there have been few outstanding advances in CdZnTe matrix detectors since then. In 2000, a new advance in the growth process made it possible to produce larger CdZnTe crystals, but the resolution was still poor due to the presence of impurities within the crystals. Recently, Brookhaven National Laboratory (BNL) has made a breakthrough in CdZnTe crystal detection technology, which may greatly improve the technology of long-distance detection of nuclear radiation. Using the National Synchrotron Light Source, scientists in the lab recently discovered that previously unnoticed "dead zones" within CdZnTe crystals cause massive deposits of tellurium within the crystal structure, greatly reducing gamma-ray resolution. Scientists at BNL have found that by finding and removing "dead zones", the resolution can be improved, resulting in a larger and more accurate detector of nuclear radiation in a CdZnTe matrix. Although the resolution of the CdZnTe detector is not yet comparable to that of the germanium detector, it is much higher than that of the sodium iodide detector.

Cadmium telluride pieces development direction

At present, two important development directions of CdZnTe detectors are: multi-block large-volume parallel detectors and panel array detectors. The former is composed of multiple CdZnTe crystal arrays with a volume greater than 1cm. This type of detector solves the shortcomings of a single detector, which is small in size and low in total detection efficiency, and greatly shortens the measurement time. It is especially suitable for portable spectrometer systems and can be used in the environment. , radioactive monitoring of ports, railway cargo, etc. The latter is composed of CdZnTe crystal panel arrays, which are mainly used in energy spectrum imaging in nuclear medicine, astrophysics and other fields. The development and use of CdZnTe detectors make it possible to obtain high-efficiency detectors for high-performance photons. With the continuous improvement of high-quality CdZnTe semiconductor crystal preparation technology, the further in-depth understanding of the carrier collection process and the rapid development of low-noise microelectronics With the development, CdZnTe detectors will be applied in a wider range of fields.