Molecular coatings of nitride semiconductors for optoelectronics, electronics, and solar energy harvesting

Abstract

Gallium nitride based semiconductors are provided having one or more passivated surfaces. The surfaces can have a plurality of thiol compounds attached thereto for enhancement of optoelectronic properties and/or solar water splitting properties. The surfaces can also include wherein the surface has been treated with chemical solution for native oxide removal and/or wherein the surface has attached thereto a plurality of nitrides, oxides, insulating compounds, thiol compounds, or a combination thereof to create a treated surface for enhancement of optoelectronic properties and/or solar water splitting properties. Methods of making the gallium nitride based semiconductors are also provided. Methods can include cleaning a native surface of a gallium nitride semiconductor to produce a cleaned surface, etching the cleaned surface to remove oxide layers on the surface, and applying single or multiple coatings of nitrides, oxides, insulating compounds, thiol compounds, or a combination thereof attached to the surface.

We claim: 
     
         1 . A semiconductor comprising: a plurality of thiol compounds attached to a semiconductor surface. 
     
     
         2 . The semiconductor of  claim 1 , wherein the plurality of thiol compounds passivates the semiconductor surface. 
     
     
         3 . The semiconductor of  claim 1 , wherein the plurality of thiol compounds forms a thin layer on the semiconductor surface. 
     
     
         4 . The semiconductor of  claim 1 , wherein the plurality of thiol compounds self-assemble to form a monolayer on the semiconductor surface. 
     
     
         5 . The semiconductor of  claim 1 , wherein the plurality of thiol compounds include one or more of monothiols having from 2 to 20 carbon atoms and dithiols having from 2 to 20 carbon atoms. 
     
     
         6 . The semiconductor of  claim 1 , wherein one or more of the plurality of thiol compounds has a structure according to formula I, formula II, a derivative thereof, or a combination thereof: 
       
         
           
           
               
               
           
         
         wherein R 2  is a C 1 -C 20  alkyl or herteroalkyl group, optionally including one or more substituents, 
         wherein R 3  is a C 1 -C 20  alkyl or herteroalkyl group, optionally including one or more substituents, and 
         wherein R 4  is hydrogen or a C 1 -C 20  alkyl or herteroalkyl group, optionally including one or more substituents. 
       
     
     
         7 . The semiconductor of  claim 6 , wherein one or both of R 2  and R 3  is a C 1 -C 3  alkyl or heteroalkyl group, optionally including one or more substituents. 
     
     
         8 . The semiconductor of  claim 1 , wherein one or more of the plurality of thiol compounds is selected from the group consisting of 1,2-ethanedithiol (EDT), 1-Pentanethiol, octadecanethiol (ODT), 1-Nonanethiol, derivatives thereof, and combinations thereof. 
     
     
         9 . The semiconductor of  claim 1 , wherein the semiconductor surface is free or essentially free of surface localized effect states originating from one or more of dangling bonds, nitrogen vacancies, and surface oxides. 
     
     
         10 . The semiconductor of  claim 1 , wherein the semiconductor is a (B,Al,Ga,In,Tl)N semiconductor, a (B,Al,Ga,In,Tl)As semiconductor, a (B,Al,Ga,In,Tl)Sb semiconductor, a (B,Al,Ga,In,Tl)Bi semiconductor, or a (B,Al,Ga,In)P semiconductor. 
     
     
         11 . The semiconductor of  claim 1 , wherein the semiconductor is selected from the group consisting of binary, quaternary, quinternary, and ternary (B, Al,Ga,In)N semiconductor alloys. 
     
     
         12 . The semiconductor of  claim 1 , wherein the semiconductor includes nanostructures, planar thin films, and bulk semiconductor materials. 
     
     
         13 . The semiconductor of  claim 1 , wherein the semiconductor includes nanowires. 
     
     
         14 . The semiconductor of  claim 13 , wherein one or more of the plurality of thiol compounds are attached to a sidewall of the nanowires. 
     
     
         15 . The semiconductor of  claim 1 , further comprising one or more of nitrides, oxides, and insulating compounds attached to the semiconductor surface. 
     
     
         16 . The semiconductor of  claim 15 , wherein the nitrides are selected from the group consisting of group-III elements such as B, Al, Ga, and In; transition metal elements such as Ta and Cr, and group-IV elements such as Si and Ge. 
     
     
         17 . The semiconductor of  claim 15 , wherein the oxides are selected from the group consisting of group-III elements such as B, Al, Ga, and In; transition metal elements such as Ta and Cr, and group-IV elements such as Si and Ge. 
     
     
         18 . The semiconductor of  claim 15 , wherein the insulating compounds are selected from the group consisting of parylene and polymer-based photoresists. 
     
     
         19 . A method of making a semiconductor of  claim 1 , the method comprising cleaning a native surface of a semiconductor to produce a cleaned semiconductor surface,
 etching the cleaned semiconductor surface to remove oxide layers on the semiconductor surface, and   applying one or more coatings of thiol compounds to the semiconductor surface to produce the semiconductor having a plurality of thiol compounds attached to the semiconductor surface.   
     
     
         20 . The method of  claim 19 , further comprising applying a coating of monolayer to 1-10000 nm containing one or more of nitrides, oxides, and insulating compounds.