SEMITIP V6, program MultInt2

Introduction

This program computes the electrostatic potential and the resulting tunnel current between a metallic tip and a nonuniform (inhomogeneous) semiconducting sample, for a 3-dimensional geometry with azimuthal symmetry. The tunnel current is computed by integrating the Schrödinger equation along the central axis of the problem (i.e. as appropriate for a planar geometry, but an approximation for a nonplanar geometry).

Version information

Version 6.6; see top of MultInt2-6.6.f source code in example(s) below for prior version information.

Usage

Source code files for the program are available in the example(s) provided below. In order to specify the inhomogeneities in the semiconductor, it is necessary to modify the source code as follows: Additional details of these source code modifications can be found in the SEMITIP V6 Technical Manual. With the appropriate modifications, the source code of the main program, together with the subroutines listed below, must by re-compiled and linked in order to produce the executable code. All input for the program (other than that modifications to the source code detailed above) comes from the file FORT.9, which is also included in the example(s) provided below.

Output

Output from the program is contained in the following files (output depends on the value of the output parameter IWRIT as specified in the input file FORT.9):

All of the parameters in the program can be varied using the input file FORT.9, with the exception of the array sizes, the specification of a surface state density other than a uniform or Gaussian shaped one, and the specification of spatial arrangement of bulk or surface charge density. See SEMITIP V6 Technical Manual for additional information on these user-defined functions. Modification of those functions can be accomplished by changing the source code of the program. The source code is available, in the following files (version numbers follow the dash in the names):

All routines are written in Fortran. The source code can be downloaded directly from the above locations, and it can be compiled and linked on any platform. Sample input and output from the program is shown in the examples below.

Illustrative Examples of Running the Code

  1. GaAs(110) with 10 nm diameter area having extrinsic states