Create folder on android

I want to store my data files in an folder accessible from the file browser. That way i cannot store my files at Application.persistantdatapath. The code ive created works well on PC, but does nothing on Android. To save and load files Im using this method. Here is my code

using UnityEngine;
using UnityEngine.UI;
using System.Collections;
using System.Collections.Generic;
using System;
using System.Runtime.Serialization.Formatters.Binary;
using System.IO;

public class SaveAndLoadMenu : MonoBehaviour {

	private TitlesList tl;
	private string pathStart;

	void Start () {
        pathStart = "/mnt/sdcard/SongFiles";

		if (Directory.Exists (pathStart) == false) {

		tl = GameObject.Find ("MenuController").GetComponent<TitlesList> ();
		Load ();

	public void Save () {
		BinaryFormatter bf = new BinaryFormatter ();
		FileStream menuFile = File.Create (pathStart + "/menu.dat");

		MenuData data = new MenuData ();

		data.titlesData = tl.titles;
		data.maxIdData = tl.maxID;
		data.idListData = tl.idList;

		bf.Serialize (menuFile, data);
		menuFile.Close ();

	public void Load () {
		if (File.Exists (pathStart + "/menu.dat")) {
			BinaryFormatter bf = new BinaryFormatter ();
			FileStream menuFile = File.Open (pathStart + "/menu.dat", FileMode.Open);
			MenuData data = (MenuData)bf.Deserialize(menuFile);

			tl.titles = data.titlesData;
			tl.maxID = data.maxIdData;
			tl.idList = data.idListData;

		//scene set-up goes here

class MenuData {
	public List<string> titlesData = new List<string>();
	public List<string> idListData = new List<string>();
	public int maxIdData;

I was trying to set the ‘pathStart’ variable to /storage/sdcard0/SongFiles, /sdcard/SongFiles and /mnt/sdcard/SongFiles, with no results on Android.

I`ve found the soution: to write files on sdcard you need to go to /edit/build settings/player settings/android and set write access to External (SdCard)