Nanoparticle‐Assisted Growth of Porous Germanium Thin Films

Abstract

[28] Note: A basic essential of this strategy is that the colloid monolayer should cover a conducting surface. However, such a surface is not suitable for synthesizing colloid monolayers in general, and it cannot be washed according to a strict procedure [17] (otherwise the conducting layer may be destroyed). Here we adopt an indirect step to make the colloid monolayer cover the conducting surface.

Photoluminescence from heterogeneous SiGe/Si nanostructures prepared via a two-step approach strategy

“…Since the first observation of strong visible luminescence from porous Si [2] in 1990, many methods such as pulse laser ablation [3], ion implantation [4], spark processing [5], low-pressure chemical vapor deposition [6,7] stained etch [8], electrochemical anodization (ECA) [9], and strain-induced Stranski-Kranstanov (SK) model [10] have been used to prepare Si-based nanostructures to mimic the porous Si, which can give rise to visible luminescence. Although the Si-based nanostructured materials as prepared via the above methods indeed show good optical properties from visible to infrared wavelength, there is still great challenge in further enhancing the optical performance because it is difficult to control size or position of the nanocrystals or to attain high density of the nanocrystals in the structure.…”

Fabrication and characteristics of porous germanium films

“…It has a potential to replace Si in advanced integrated optoelectronic devices because of its higher mobility of holes and electrons, smaller band gap, larger effective Bohr radius (24 nm at 300 K), and higher solubility of dopants [7][8][9][10]. The work on porous Ge is limited by the lack of adequate procedures for its fabrication [2,3]. It has been particularly challenging to synthesize group IV materials, such as Si and Ge, primarily owing to their strong covalent bonding and the need for high temperatures to promote crystallization [11][12][13].…”

“…It has been particularly challenging to synthesize group IV materials, such as Si and Ge, primarily owing to their strong covalent bonding and the need for high temperatures to promote crystallization [11][12][13]. Anodization and electrochemical etching [3,[14][15][16][17][18], spark processing [19,20] and inductively coupled plasma chemical vapor deposition (ICPCVD) [2,21] have been used to prepare porous Ge films. It is still a challenge to produce porous, semiconducting and luminescent Ge films in a simple and robust way, allowing their subsequent processing and integration into working devices [1][2][3][14][15][16][17][18][19][20].…”

“…Porous semiconductor materials with visible photoluminescence (PL) are a topic of intense interest owing to their unique optoelectronic and morphological properties, as well as biocompatibility characteristics [1][2][3][4]. In the last decade, most research efforts have concentrated on porous silicon [4][5][6].…”

“…Anodization and electrochemical etching [3,[14][15][16][17][18], spark processing [19,20] and inductively coupled plasma chemical vapor deposition (ICPCVD) [2,21] have been used to prepare porous Ge films. It is still a challenge to produce porous, semiconducting and luminescent Ge films in a simple and robust way, allowing their subsequent processing and integration into working devices [1][2][3][14][15][16][17][18][19][20]. The porous structure plays an important role in the visible PL emission of the indirect bandgap semiconductors, such as Si and Ge [4][5][6][14][15][16][17][18][19][20].…”