How to write byte in the file

Dim Fs As System.IO.FileStream
Dim TempFileName As String
Dim RBytes() As Byte
TempFileName = System.IO.Path.GetTempFileName()
Fs = New System.IO.FileStream(TempFileName, IO.FileMode.Create, IO.FileAccess.Write)
Fs.Write(RBytes, 0, RBytes.Length)
Fs.Close()
Return TempFileName