Germanium and germanium alloy nanoparticle and method for producing the same

Abstract

In the invention, an electrochemical etching of crystalline germanium or a germanium alloy produces well-segregated chromatic clusters of nanoparticles. Distinct strong bands appear in the photoluminescence spectra under 350 nm excitation with the lowest peaks in wavelength identified to be at 430, 480, and 580 and 680-1100 nm. The material may be dispersed into a discrete set of luminescent nanoparticles of 1-3 nm in diameter, which may be prepared into colloids and reconstituted into films, crystals, etc.

1 . A method for producing elemental germanium or germanium alloy nanoparticles, the method comprising steps of: 
 contacting a germanium or germanium alloy electrode with an etchant solution;    providing a flow of electrical current to a surface of the germanium or germanium alloy electrode through application of electrical potential between the germanium or germanium alloy electrode and another electrode;    reversing the electrical potential and repeating said step of providing;    separating the germanium or germanium alloy electrode from the etchant solution.    
     
     
         2 . The method according to  claim 1 , further comprising a step of: 
 separating germanium or germanium alloy nanoparticles from the germanium or germanium alloy electrode.    
     
     
         3 . The method according to  claim 2 , wherein said step of separating germanium or germanium alloy nanoparticles comprises: 
 subjecting the germanium or germanium alloy electrode to force to separate germanium or germanium alloy nanoparticles from the germanium or germanium alloy electrode.    
     
     
         4 . The method according to  claim 3 , wherein the force in said step of subjecting is provided by ultrasound waves.  
     
     
         5 . The method according to  claim 2 , wherein said step of separating germanium or germanium alloy nanoparticles comprises: 
 placing the germanium or germanium alloy electrode in a solvent and subjecting the germanium or germanium alloy electrode to force to separate germanium or germanium alloy nanoparticles from the germanium or germanium alloy electrode.    
     
     
         6 . The method of  claim 5 , further comprising a step of rinsing the germanium or germanium alloy electrode subsequent to said step of separating and prior to said step of placing the germanium or germanium alloy electrode in a solvent solution.  
     
     
         7 . The method according to  claim 1 , wherein said step of contacting comprises gradually advancing the germanium or germanium alloy into the etchant solution.  
     
     
         8 . The method according to  claim 1 , further comprising a step of doping the germanium or germanium alloy nanoparticles.  
     
     
         9 . The method according to  claim 1 , further comprising a step of coating the germanium or germanium alloy nanoparticles.  
     
     
         10 . The method according to  claim 9 , wherein said step of coating comprises coating said particles with biological material.  
     
     
         11 . The method according to  claim 1 , wherein the another electrode is formed from platinum, and the germanium or germanium alloy electrode comprises a single crystalline germanium.  
     
     
         12 . The method according to  claim 1 , wherein the germanium or germanium alloy electrode comprises p-type boron-doped germanium.  
     
     
         13 . The method according to  claim 1 , wherein the etchant solution comprises HF/H 2 O 2 /H 2 O and methanol.  
     
     
         14 . The method according to  claim 13 , wherein the etchant solution further comprises a Ge salt solution.  
     
     
         15 . The method according to  claim 13 , wherein the etchant solution further comprises granular germanium.  
     
     
         16 . The method according to  claim 1 , wherein the etchant solution comprises HCl and methanol.  
     
     
         17 . The method according to  claim 16 , wherein the etchant solution further comprises a Ge salt solution.  
     
     
         18 . The method according to  claim 16 , wherein the etchant solution further comprises granular germanium.  
     
     
         19 . A method for producing elemental germanium or germanium alloy nanoparticles, the method comprising steps of: 
 contacting bulk germanium with a chemical etchant solution;    bipolar electrochemically etching the bulk germanium during said step of contacting; and    separating the germanium or germanium alloy electrode from the etchant solution.    
     
     
         20 . The method according to  claim 19 , wherein said step of contacting comprises gradually advancing the germanium or germanium alloy into the etchant solution.  
     
     
         21 . The method according to  claim 19 , wherein the etchant solution comprises HF/H 2 O 2 /H 2 O and methanol.  
     
     
         22 . The method according to  claim 21 , wherein the etchant solution further comprises a Ge salt solution.  
     
     
         23 . The method according to  claim 21 , wherein the etchant solution further comprises granular germanium.  
     
     
         24 . The method according to  claim 19 , wherein the etchant solution comprises HCl and methanol.  
     
     
         25 . The method according to  claim 24 , wherein the etchant solution further comprises a Ge salt solution.  
     
     
         26 . The method according to  claim 24 , wherein the etchant solution further comprises granular germanium.  
     
     
         27 . Elemental Germanium material comprising nanoparticles dimensioned in the range of ˜1-3 nm.  
     
     
         28 . Germanium alloy material comprising nanoparticles dimensioned in the range of ˜1-3 nm.