Hodes Gary
Dept. of Materials and Interfaces Weizmann Institute of Science, Rehovot, 76100, Israel.
Phys Chem Chem Phys. 2007 Jun 14;9(18):2181-96. doi: 10.1039/b616684a. Epub 2007 Feb 9.
Chemical bath deposition (CBD) has been used to deposit films of metal sulfides, selenides and oxides, together with some miscellaneous compounds, beginning nearly 140 years ago. While it is a well-known technique in a few specific areas (notably photoconductive lead salt detectors, photoelectrodes and more recently, thin film solar cells), it is by and large an under-appreciated technique. The more recent interest in all things 'nano' has provided a boost for CBD: since it is a low temperature, solution (almost always aqueous) technique, crystal size is often very small. This is evidenced by the existence of size quantization commonly found in CBD semiconductor films. The intention of this review is to provide readers, many of whom may not even be aware of the CBD technique, with an overview of how the technique has been used to fabricate nanocrystalline semiconductor (this terminology also includes oxides often classified as ceramics) films and some properties of these films. The review begins, after a short introduction, with a general description of the CBD method, designed to give the reader a basic knowledge of the technique. The rest of the review then focuses on nanocrystalline (or, in the few cases of amorphous deposits, nanoparticle) films. The various factors which determine crystal size are first discussed. This is followed by some of the many examples of size quantization observed in the films. Since CBD films are usually porous, surface effects can be very important, and various surface-dependent properties (light emission and surface states) as well as surface modification, are treated: (although some properties, like emission, can be strongly dependent on both surface and 'bulk'). Because of the fact that many CBD films have been made specifically for use as photoelectrodes in photoelectrochemical cells, there is next a chapter on this topic with a few examples of such photoelectrodes. Film structure and morphology follows with examples of patterning, porosity and crystal shape. The review concludes with some of the author's opinions as to what the near future holds for CBD development in general.
近140年前起，化学浴沉积（CBD）就已被用于沉积金属硫化物、硒化物和氧化物薄膜，以及一些其他化合物薄膜。虽然在一些特定领域（尤其是光电导铅盐探测器、光电极以及最近的薄膜太阳能电池）它是一种广为人知的技术，但总体而言，它是一种未得到充分重视的技术。最近对所有“纳米”事物的兴趣为CBD带来了推动：由于它是一种低温、溶液（几乎总是水性）技术，晶体尺寸通常非常小。这在CBD半导体薄膜中常见的尺寸量子化现象中得到了证明。这篇综述的目的是为读者（其中许多人甚至可能不知道CBD技术）提供一个概述，介绍该技术如何用于制造纳米晶半导体（这个术语也包括通常归类为陶瓷的氧化物）薄膜以及这些薄膜的一些特性。在简短的引言之后，综述首先对CBD方法进行了一般性描述，旨在让读者对该技术有基本的了解。然后综述的其余部分聚焦于纳米晶（或者在少数非晶沉积物的情况下，纳米颗粒）薄膜。首先讨论了决定晶体尺寸的各种因素。接下来是在薄膜中观察到的许多尺寸量子化的例子。由于CBD薄膜通常是多孔的，表面效应可能非常重要，因此对各种与表面相关的特性（发光和表面态）以及表面改性进行了探讨：（尽管一些特性，如发光，可能强烈依赖于表面和“体相”两者）。由于许多CBD薄膜是专门为用作光电化学电池中的光电极而制备的，接下来有一章关于这个主题，并给出了一些此类光电极的例子。随后是薄膜结构和形态，包括图案化、孔隙率和晶体形状的例子。综述最后是作者对CBD总体发展的近期前景的一些看法。
