SharePoint REST Create Folder

function createListFolder(siteUrl, listName, foldername) {
    var serverUrl = _spPageContextInfo.webAbsoluteUrl;
    $.ajax({
        url: serverUrl + "/_api/Web/Folders/add(‘"+listName+"/"+ foldername+"‘)",
        type: "POST",
        headers: {
            "accept": "application/json; odata=verbose",
            "content-type": "application/json; odata=verbose",
            "X-RequestDigest": $("#__REQUESTDIGEST").val()
        },
        error: function (data) {
            alert(data.responseText);
            //alert("fail");
        }
    });
}