Quantum well

v0 = 8.;
hb = 1.;
d  = 1.;
m  = 1.;

V = (*TB[*)Piecewise[{{(*|*)0(*|*),(*|*)-d<=#<d(*|*)},{(*|*)v0(*|*),(*|*)True(*|*)}}](*|*)(*1:eJxTTMoPSmNkYGAo5gESAZmpyanlmcWpTvkVmUxAAQBzVQdd*)(*]TB*) &;
op[u_[x_]] := - hb^2/(2 m) u''[x] + V[x] u[x];

controls = EventHandler[InputGroup[<|
  "m" -> InputRange[0.1, 5, 1.0, 1.0, "Label"->"Mass"],
  "V" -> InputRange[0.1, 10, 1.0, 8.0, "Label"->"V0"],
  "d" -> InputRange[0.1, 2, 0.5, 1.0, "Label"->"d"]
|>], Function[values,
      v0 = values["V"];
      m = values["m"];
      d = values["d"];
  
      vplot = Table[{x,V[x]}, {x,-2,2,0.05}];
      
      {ev, ef} = 
        NDEigensystem[{op[u[x]], DirichletCondition[u[x] == 0, True]}, u[x], {x, -2, 2}, 6];
      
      xaxis = Table[i, {i,-2,2,0.025}];
      yaxis = Table[Evaluate[ef + ev], {x, xaxis}] // Transpose;
]];

controls // EventFire;

Row[
    {
        Graphics[
            {
                Table[
                    With[{i = i, color = ColorData[97][i]},
                        {color, Line[{xaxis, yaxis[[i]]} // Transpose
                            ] // Offload}
                    ]
                    ,
                    {i, Length[yaxis]}
                ]
                ,
                AbsoluteThickness[2]
                ,
                Line[vplot // Offload]
            }
            ,
            Axes -> True
            ,
            PlotRange -> {{-2, 2}, {0, 16}}
            ,
            ImageSize -> {350, 350}
        ]
        ,
        controls
    }
]

(*GB[*){{(*VB[*)(FrontEndRef["88343d8d-6429-47ba-ad68-6d5bc17aeccd"])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgEKW1gYmxinWKTompkYWeqamCcl6iammFnomqWYJiUbmiemJienAAB94BYP"*)(*]VB*)(*|*),(*|*)(*VB[*)(EventObject[<|"Id" -> "9f1cd6cf-3c45-4198-ab48-a15dd669c1ce", "Initial" -> <|"m" -> 1., "V" -> 8., "d" -> 1.|>, "View" -> "036730f0-8219-4c21-9547-2ecc0b0186e7"|>])(*,*)(*"1:eJxTTMoPSmNkYGAoZgESHvk5KRCeEJBwK8rPK3HNS3GtSE0uLUlMykkNVgEKGxibmRsbpBnoWhgZWuqaJBsZ6lqampjrGqUmJxskGRhamKWaAwBrcBSt"*)(*]VB*)}}(*]GB*)